term paper nuclear bomb

Information

Select Page

An underachieving Princeton student wrote a term paper describing how to make a nuclear bomb. It was seized by the FBI

In 1976, John Aristotle Phillips was an underachieving student at Princeton. In order to improve his grades, he wrote a term paper on nuclear proliferation. The report included designs for an atomic bomb similar to the one dropped on Nagasaki. He used publicly available books and papers to create the design. He got an A+ on the report, and promptly had it seized by the FBI.

“I wanted it to be simple, inexpensive and easy to build,” said Phillips, 21, the son of a Yale engineering professor. “The idea was not to use any classified information. I wanted to do it with what was available to the public.” According to nuclear physicist Frank Chilton of Palo Alto, Calif., the Princeton student has overcome some of the major pitfalls in building a nuclear device. He says it’s 20 years behind the time, but still more sophisticated than the Hiroshima bomb. Phillips hasn’t actually built the bomb, but it would be about the size of a beachball and weigh 125 pounds. Page 20 of Phillips’ research paper had been withheld from public view: It deals with the key problem of the type of high-explosive component needed to trigger the nuclear blast. Phillips figured out the answer with the aid of nuclear engineering textbooks and two U.S. government publications. Says Phillips: “It’s very simple. Any undergraduate physics major could have done what I did.” ( Source )

In February 1977, several months after the story first went public, Phillips was contacted by a Pakistani official trying to purchase the bomb design. By that point the Federal Bureau of Investigation had confiscated Phillips’s term paper along with a mockup of the bomb he had constructed in his dormitory room.

As of 2016, Phillips is in the business of political data mining—he finds out everything he can about individual voters and then sells that information to politicians. Aristotle’s massive private database contains detailed information on roughly 175 million American voters. The company was founded in 1983. ( Source )

FURTHER READING Mushroom: The True Story of the A-Bomb Kid , John Aristotle Phillips, 1979 People Magazine: A Princeton Tiger Designs An Atomic Bomb in a Physics Class, 1976 Vanity Fair: BIG BROTHER INC., 2007

Related Posts

Stunning old map of Holyoke, Mass from 1877

April 15, 2017

Beautifully restored map of Hackettstown, NJ from 1883

July 18, 2016

Vintage hand-colored map of Connecticut from 1857

October 7, 2017

Historic bird’s eye view of Annapolis, Maryland from 1864

August 2, 2017

Knowledge & Wisdom

Recent Posts

Pin It on Pinterest

The Atomic Bomb and the End of World War II

A Collection of Primary Sources

Updated National Security Archive Posting Marks 75th Anniversary of the Atomic Bombings of Japan and the End of World War II

Extensive Compilation of Primary Source Documents Explores Manhattan Project, Eisenhower’s Early Misgivings about First Nuclear Use, Curtis LeMay and the Firebombing of Tokyo, Debates over Japanese Surrender Terms, Atomic Targeting Decisions, and Lagging Awareness of Radiation Effects

Washington, D.C., August 4, 2020 –  To mark the 75th anniversary of the atomic bombings of Hiroshima and Nagasaki in August 1945, the National Security Archive is updating and reposting one of its most popular e-books of the past 25 years. 

While U.S. leaders hailed the bombings at the time and for many years afterwards for bringing the Pacific war to an end and saving untold thousands of American lives, that interpretation has since been seriously challenged.  Moreover, ethical questions have shrouded the bombings which caused terrible human losses and in succeeding decades fed a nuclear arms race with the Soviet Union and now Russia and others.

Three-quarters of a century on, Hiroshima and Nagasaki remain emblematic of the dangers and human costs of warfare, specifically the use of nuclear weapons.  Since these issues will be subjects of hot debate for many more years, the Archive has once again refreshed its compilation of declassified U.S. government documents and translated Japanese records that first appeared on these pages in 2005.

*    *    *    *    *

Introduction

By William Burr

The 75th anniversary of the atomic bombings of Hiroshima and Nagasaki in August 1945 is an occasion for sober reflection. In Japan and elsewhere around the world, each anniversary is observed with great solemnity. The bombings were the first time that nuclear weapons had been detonated in combat operations.  They caused terrible human losses and destruction at the time and more deaths and sickness in the years ahead from the radiation effects. And the U.S. bombings hastened the Soviet Union’s atomic bomb project and have fed a big-power nuclear arms race to this day. Thankfully, nuclear weapons have not been exploded in war since 1945, perhaps owing to the taboo against their use shaped by the dropping of the bombs on Japan. 

Along with the ethical issues involved in the use of atomic and other mass casualty weapons, why the bombs were dropped in the first place has been the subject of sometimes heated debate. As with all events in human history, interpretations vary and readings of primary sources can lead to different conclusions.  Thus, the extent to which the bombings contributed to the end of World War II or the beginning of the Cold War remain live issues.  A significant contested question is whether, under the weight of a U.S. blockade and massive conventional bombing, the Japanese were ready to surrender before the bombs were dropped.  Also still debated is the impact of the Soviet declaration of war and invasion of Manchuria, compared to the atomic bombings, on the Japanese decision to surrender. Counterfactual issues are also disputed, for example whether there were alternatives to the atomic bombings, or would the Japanese have surrendered had a demonstration of the bomb been used to produced shock and awe. Moreover, the role of an invasion of Japan in U.S. planning remains a matter of debate, with some arguing that the bombings spared many thousands of American lives that otherwise would have been lost in an invasion.

Those and other questions will be subjects of discussion well into the indefinite future. Interested readers will continue to absorb the fascinating historical literature on the subject.  Some will want to read declassified primary sources so they can further develop their own thinking about the issues. Toward that end, in 2005, at the time of the 60th anniversary of the bombings, staff at the National Security Archive compiled and scanned a significant number of declassified U.S. government documents to make them more widely available. The documents cover multiple aspects of the bombings and their context.  Also included, to give a wider perspective, were translations of Japanese documents not widely available before.  Since 2005, the collection has been updated. This latest iteration of the collection includes corrections, a few minor revisions, and updated footnotes to take into account recently published secondary literature.

2015 Update

August 4, 2015 – A few months after the atomic bombings of Hiroshima and Nagasaki, General Dwight D.  Eisenhower commented during a social occasion “how he had hoped that the war might have ended without our having to use the atomic bomb.” This virtually unknown evidence from the diary of Robert P. Meiklejohn, an assistant to Ambassador W. Averell Harriman, published for the first time today by the National Security Archive, confirms that the future President Eisenhower had early misgivings about the first use of atomic weapons by the United States. General George C. Marshall is the only high-level official whose contemporaneous (pre-Hiroshima) doubts about using the weapons against cities are on record.

On the 70th anniversary of the bombing of Hiroshima on August 6, 1945, the National Security Archive updates its 2005 publication of the most comprehensive on-line collection of declassified U.S. government documents on the first use of the atomic bomb and the end of the war in the Pacific. This update presents previously unpublished material and translations of difficult-to-find records. Included are documents on the early stages of the U.S. atomic bomb project, Army Air Force General  Curtis LeMay’s report  on the firebombing of Tokyo (March 1945), Secretary of War Henry  Stimson’s requests  for modification of unconditional surrender terms,  Soviet documents  relating to the events, excerpts from the Robert P. Meiklejohn diaries mentioned above, and selections from the diaries of Walter J. Brown, special assistant to Secretary of State James Byrnes.

The original 2005 posting included a wide range of material, including formerly top secret "Magic" summaries of intercepted Japanese communications and the first-ever full translations from the Japanese of accounts of high level meetings and discussions in Tokyo leading to the Emperor’s decision to surrender. Also documented are U.S. decisions to target Japanese cities, pre-Hiroshima petitions by scientists questioning the military use of the A-bomb, proposals for demonstrating the effects of the bomb, debates over whether to modify unconditional surrender terms, reports from the bombing missions of Hiroshima and Nagasaki, and belated top-level awareness of the radiation effects of atomic weapons.

The documents can help readers to make up their own minds about long-standing controversies such as whether the first use of atomic weapons was justified, whether President Harry S. Truman had alternatives to atomic attacks for ending the war, and what the impact of the Soviet declaration of war on Japan was. Since the 1960s, when the declassification of important sources began, historians have engaged in vigorous debate over the bomb and the end of World War II. Drawing on sources at the National Archives and the Library of Congress as well as Japanese materials, this electronic briefing book includes key documents that historians of the events have relied upon to present their findings and advance their interpretations.

The Atomic Bomb and the End of World War II: A Collection of Primary Sources

Seventy years ago this month, the United States dropped atomic bombs on Hiroshima and Nagasaki, the Soviet Union declared war on Japan, and the Japanese government surrendered to the United States and its allies. The nuclear age had truly begun with the first military use of atomic weapons. With the material that follows, the National Security Archive publishes the most comprehensive on-line collection to date of declassified U.S. government documents on the atomic bomb and the end of the war in the Pacific. Besides material from the files of the Manhattan Project, this collection includes formerly “Top Secret Ultra” summaries and translations of Japanese diplomatic cable traffic intercepted under the “Magic” program. Moreover, the collection includes for the first time translations from Japanese sources of high level meetings and discussions in Tokyo, including the conferences when Emperor Hirohito authorized the final decision to surrender. [1]

Ever since the atomic bombs were exploded over Japanese cities, historians, social scientists, journalists, World War II veterans, and ordinary citizens have engaged in intense controversy about the events of August 1945. John Hersey’s  Hiroshima , first published in the New Yorker  in 1946 encouraged unsettled readers to question the bombings while church groups and some commentators, most prominently Norman Cousins, explicitly criticized them. Former Secretary of War Henry Stimson found the criticisms troubling and published an influential justification for the attacks in  Harper’s . [2] During the 1960s the availability of primary sources made historical research and writing possible and the debate became more vigorous. Historians Herbert Feis and Gar Alperovitz raised searching questions about the first use of nuclear weapons and their broader political and diplomatic implications. The controversy, especially the arguments made by Alperovitz and others about “atomic diplomacy” quickly became caught up in heated debates over Cold War “revisionism.” The controversy simmered over the years with major contributions by Martin Sherwin and Barton J. Bernstein but it became explosive during the mid-1990s when curators at the National Air and Space Museum met the wrath of the Air Force Association over a proposed historical exhibit on the Enola Gay. [3] The NASM exhibit was drastically scaled-down but historians and journalist continued to engage in the debate. Alperovitz, Bernstein, and Sherwin made new contributions as did other historians, social scientists, and journalists including Richard B. Frank, Herbert Bix, Sadao Asada, Kai Bird, Robert James Maddox, Sean Malloy, Robert P. Newman, Robert S. Norris, Tsuyoshi Hagesawa, and J. Samuel Walker. [4]

The continued controversy has revolved around the following, among other, questions:

• were the atomic strikes necessary primarily to avert an invasion of Japan in November 1945?
• Did Truman authorize the use of atomic bombs for diplomatic-political reasons-- to intimidate the Soviets--or was his major goal to force Japan to surrender and bring the war to an early end?
• If ending the war quickly was the most important motivation of Truman and his advisers to what extent did they see an “atomic diplomacy” capability as a “bonus”?
• To what extent did subsequent justification for the atomic bomb exaggerate or misuse wartime estimates for U.S. casualties stemming from an invasion of Japan?
• Were there alternatives to the use of the weapons? If there were, what were they and how plausible are they in retrospect? Why were alternatives not pursued?
• How did the U.S. government plan to use the bombs? What concepts did war planners use to select targets? To what extent were senior officials interested in looking at alternatives to urban targets? How familiar was President Truman with the concepts that led target planners chose major cities as targets?
• What did senior officials know about the effects of atomic bombs before they were first used. How much did top officials know about the radiation effects of the weapons?
• Did President Truman make a decision, in a robust sense, to use the bomb or did he inherit a decision that had already been made?
• Were the Japanese ready to surrender before the bombs were dropped? To what extent had Emperor Hirohito prolonged the war unnecessarily by not seizing opportunities for surrender?
• If the United States had been more flexible about the demand for “unconditional surrender” by explicitly or implicitly guaranteeing a constitutional monarchy would Japan have surrendered earlier than it did?
• How decisive was the atomic bombings to the Japanese decision to surrender?
• Was the bombing of Nagasaki unnecessary? To the extent that the atomic bombing was critically important to the Japanese decision to surrender would it have been enough to destroy one city?
• Would the Soviet declaration of war have been enough to compel Tokyo to admit defeat?
• Was the dropping of the atomic bombs morally justifiable?

This compilation will not attempt to answer these questions or use primary sources to stake out positions on any of them. Nor is it an attempt to substitute for the extraordinary rich literature on the atomic bombings and the end of World War II. Nor does it include any of the interviews, documents prepared after the events, and post-World War II correspondence, etc. that participants in the debate have brought to bear in framing their arguments. Originally this collection did not include documents on the origins and development of the Manhattan Project, although this updated posting includes some significant records for context. By providing access to a broad range of U.S. and Japanese documents, mainly from the spring and summer of 1945, interested readers can see for themselves the crucial source material that scholars have used to shape narrative accounts of the historical developments and to frame their arguments about the questions that have provoked controversy over the years. To help readers who are less familiar with the debates, commentary on some of the documents will point out, although far from comprehensively, some of the ways in which they have been interpreted. With direct access to the documents, readers may develop their own answers to the questions raised above. The documents may even provoke new questions.

Contributors to the historical controversy have deployed the documents selected here to support their arguments about the first use of nuclear weapons and the end of World War II. The editor has closely reviewed the footnotes and endnotes in a variety of articles and books and selected documents cited by participants on the various sides of the controversy. [5] While the editor has a point of view on the issues, to the greatest extent possible he has tried to not let that influence document selection, e.g., by selectively withholding or including documents that may buttress one point of view or the other. The task of compilation involved consultation of primary sources at the National Archives, mainly in Manhattan Project files held in the records of the Army Corps of Engineers, Record Group 77, but also in the archival records of the National Security Agency. Private collections were also important, such as the Henry L. Stimson Papers held at Yale University (although available on microfilm, for example, at the Library of Congress) and the papers of W. Averell Harriman at the Library of Congress. To a great extent the documents selected for this compilation have been declassified for years, even decades; the most recent declassifications were in the 1990s.

The U.S. documents cited here will be familiar to many knowledgeable readers on the Hiroshima-Nagasaki controversy and the history of the Manhattan Project. To provide a fuller picture of the transition from U.S.-Japanese antagonism to reconciliation, the editor has done what could be done within time and resource constraints to present information on the activities and points of view of Japanese policymakers and diplomats. This includes a number of formerly top secret summaries of intercepted Japanese diplomatic communications, which enable interested readers to form their own judgments about the direction of Japanese diplomacy in the weeks before the atomic bombings. Moreover, to shed light on the considerations that induced Japan’s surrender, this briefing book includes new translations of Japanese primary sources on crucial events, including accounts of the conferences on August 9 and 14, where Emperor Hirohito made decisions to accept Allied terms of surrender.

[ Editor’s Note: Originally prepared in July 2005 this posting has been updated, with new documents, changes in organization, and other editorial changes. As noted, some documents relating to the origins of the Manhattan Project have been included in addition to entries from the Robert P. Meiklejohn diaries and translations of a few Soviet documents, among other items. Moreover, recent significant contributions to the scholarly literature have been taken into account.]

I. Background on the U.S. Atomic Project

Documents 1A-C: Report of the Uranium Committee

1A . Arthur H. Compton, National Academy of Sciences Committee on Atomic Fission, to Frank Jewett, President, National Academy of Sciences, 17 May 1941, Secret

1B . Report to the President of the National Academy of Sciences by the Academy Committee on Uranium, 6 November 1941, Secret

1C . Vannevar Bush, Director, Office of Scientific Research and Development, to President Roosevelt, 27 November 1941, Secret

Source: National Archives, Records of the Office of Scientific Research and Development, Record Group 227 (hereinafter RG 227), Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section A (1940-1941)."

This set of documents concerns the work of the Uranium Committee of the National Academy of Sciences, an exploratory project that was the lead-up to the actual production effort undertaken by the Manhattan Project. The initial report, May 1941, showed how leading American scientists grappled with the potential of nuclear energy for military purposes. At the outset, three possibilities were envisioned: radiological warfare, a power source for submarines and ships, and explosives. To produce material for any of those purposes required a capability to separate uranium isotopes in order to produce fissionable U-235. Also necessary for those capabilities was the production of a nuclear chain reaction. At the time of the first report, various methods for producing a chain reaction were envisioned and money was being budgeted to try them out.

Later that year, the Uranium Committee completed its report and OSRD Chairman Vannevar Bush reported the findings to President Roosevelt: As Bush emphasized, the U.S. findings were more conservative than those in the British MAUD report: the bomb would be somewhat “less effective,” would take longer to produce, and at a higher cost. One of the report’s key findings was that a fission bomb of superlatively destructive power will result from bringing quickly together a sufficient mass of element U235.” That was a certainty, “as sure as any untried prediction based upon theory and experiment can be.” The critically important task was to develop ways and means to separate highly enriched uranium from uranium-238. To get production going, Bush wanted to establish a “carefully chosen engineering group to study plans for possible production.” This was the basis of the Top Policy Group, or the S-1 Committee, which Bush and James B. Conant quickly established. [6]

In its discussion of the effects of an atomic weapon, the committee considered both blast and radiological damage. With respect to the latter, “It is possible that the destructive effects on life caused by the intense radioactivity of the products of the explosion may be as important as those of the explosion itself.” This insight was overlooked when top officials of the Manhattan Project considered the targeting of Japan during 1945. [7]

Documents 2A-B: Going Ahead with the Bomb

2A : Vannevar Bush to President Roosevelt, 9 March 1942, with memo from Roosevelt attached, 11 March 1942, Secret

2B : Vannevar Bush to President Roosevelt, 16 December 1942, Secret (report not attached)

Sources: 2A: RG 227, Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section II (1941-1942): 2B: Bush-Conant papers, S-1 Historical File, Reports to and Conferences with the President (1942-1944)

The Manhattan Project never had an official charter establishing it and defining its mission, but these two documents are the functional equivalent of a charter, in terms of presidential approvals for the mission, not to mention for a huge budget. In a progress report, Bush told President Roosevelt that the bomb project was on a pilot plant basis, but not yet at the production stage. By the summer, once “production plants” would be at work, he proposed that the War Department take over the project. In reply, Roosevelt wrote a short memo endorsing Bush’s ideas as long as absolute secrecy could be maintained. According to Robert S. Norris, this was “the fateful decision” to turn over the atomic project to military control. [8]

Some months later, with the Manhattan Project already underway and under the direction of General Leslie Grove, Bush outlined to Roosevelt the effort necessary to produce six fission bombs. With the goal of having enough fissile material by the first half of 1945 to produce the bombs, Bush was worried that the Germans might get there first. Thus, he wanted Roosevelt’s instructions as to whether the project should be “vigorously pushed throughout.” Unlike the pilot plant proposal described above, Bush described a real production order for the bomb, at an estimated cost of a “serious figure”: $400 million, which was an optimistic projection given the eventual cost of $1.9 billion. To keep the secret, Bush wanted to avoid a “ruinous” appropriations request to Congress and asked Roosevelt to ask Congress for the necessary discretionary funds. Initialed by President Roosevelt (“VB OK FDR”), this may have been the closest that he came to a formal approval of the Manhattan Project.

Document 3 : Memorandum by Leslie R. Grove, “Policy Meeting, 5/5/43,” Top Secret

Source:  National Archives, Record Group 77, Records of the Army Corps of Engineers (hereinafter RG 77), Manhattan Engineering District (MED), Minutes of the Military Policy Meeting (5 May 1943), Correspondence (“Top Secret”) of the Manhattan Engineer District, 1942-1946, microfilm publication M1109 (Washington, D.C.: National Archives and Records Administration, 1980), Roll 3, Target 6, Folder 23, “Military Policy Committee, Minutes of Meetings”

Before the Manhattan Project had produced any weapons, senior U.S. government officials had Japanese targets in mind. Besides discussing programmatic matters (e.g., status of gaseous diffusion plants, heavy water production for reactors, and staffing at Las Alamos), the participants agreed that the first use could be Japanese naval forces concentrated at Truk Harbor, an atoll in the Caroline Islands. If there was a misfire the weapon would be difficult for the Japanese to recover, which would not be the case if Tokyo was targeted. Targeting Germany was rejected because the Germans were considered more likely to “secure knowledge” from a defective weapon than the Japanese. That is, the United States could possibly be in danger if the Nazis acquired more knowledge about how to build a bomb. [9]

Document 4 :   Memo from General Groves to the Chief of Staff [Marshall], “Atomic Fission Bombs – Present Status and Expected Progress,” 7 August 1944, Top Secret, excised copy

Source: RG 77, Correspondence ("Top Secret") of the Manhattan Engineer District, 1942-1946, file 25M

This memorandum from General Groves to General Marshall captured how far the Manhattan Project had come in less than two years since Bush’s December 1942 report to President Roosevelt .  Groves did not mention this but around the time he wrote this the Manhattan Project had working at its far-flung installations over  125,000 people  ; taking into account high labor turnover some 485,000 people worked on the project (1 out of every 250 people in the country at that time). What these people were laboring to construct, directly or indirectly, were two types of weapons—a gun-type weapon using U-235 and an implosion weapon using plutonium (although the possibility of U-235 was also under consideration). As the scientists had learned, a gun-type weapon based on plutonium was “impossible” because that element had an “unexpected property”: spontaneous neutron emissions would cause the weapon to “fizzle.” [10]  For both the gun-type and the implosion weapons, a production schedule had been established and both would be available during 1945. The discussion of weapons effects centered on blast damage models; radiation and other effects were overlooked.

Document 5 : Memorandum from Vannevar Bush and James B. Conant, Office of Scientific Research and Development, to Secretary of War, September 30, 1944, Top Secret

Source: RG 77, Harrison-Bundy Files (H-B Files), folder 69 (copy from microfilm)

While Groves worried about the engineering and production problems, key War Department advisers were becoming troubled over the diplomatic and political implications of these enormously powerful weapons and the dangers of a global nuclear arms race. Concerned that President Roosevelt had an overly “cavalier” belief about the possibility of maintaining a post-war Anglo-American atomic monopoly, Bush and Conant recognized the limits of secrecy and wanted to disabuse senior officials of the notion that an atomic monopoly was possible. To suggest alternatives, they drafted this memorandum about the importance of the international exchange of information and international inspection to stem dangerous nuclear competition. [11]

Documents 6A-D: President Truman Learns the Secret:

6A : Memorandum for the Secretary of War from General L. R. Groves, “Atomic Fission Bombs,” April 23, 1945

6B : Memorandum discussed with the President, April 25, 1945

6C : [Untitled memorandum by General L.R. Groves, April 25, 1945

6D : Diary Entry, April 25, 1945

Sources: A: RG 77, Commanding General’s file no. 24, tab D; B: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress); C: Source: Record Group 200, Papers of General Leslie R. Groves, Correspondence 1941-1970, box 3, “F”; D: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

Soon after he was sworn in as president following President Roosevelt’s death, Harry Truman learned about the top secret Manhattan Project from a briefing from Secretary of War Stimson and Manhattan Project chief General Groves, who went through the “back door” to escape the watchful press. Stimson, who later wrote up the meeting in his diary, also prepared a discussion paper, which raised broader policy issues associated with the imminent possession of “the most terrible weapon ever known in human history.” In a background report prepared for the meeting, Groves provided a detailed overview of the bomb project from the raw materials to processing nuclear fuel to assembling the weapons to plans for using them, which were starting to crystallize.

With respect to the point about assembling the weapons, the first gun-type weapon “should be ready about 1 August 1945” while an implosion weapon would also be available that month. “The target is and was always expected to be Japan.” The question whether Truman “inherited assumptions” from the Roosevelt administration that that the bomb would be used has been a controversial one. Alperovitz and Sherwin have argued that Truman made “a real decision” to use the bomb on Japan by choosing “between various forms of diplomacy and warfare.” In contrast, Bernstein found that Truman “never questioned [the] assumption” that the bomb would and should be used. Norris also noted that “Truman’s `decision’ was a decision not to override previous plans to use the bomb.” [12]

II. Targeting Japan

Document 7 : Commander F. L. Ashworth to Major General L.R. Groves, “The Base of Operations of the 509 th  Composite Group,” February 24, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5g

The force of B-29 nuclear delivery vehicles that was being readied for first nuclear use—the Army Air Force’s 509 th  Composite Group—required an operational base in the Western Pacific. In late February 1945, months before atomic bombs were ready for use, the high command selected Tinian, an island in the Northern Marianas Islands, for that base.

Document 8 : Headquarters XXI Bomber Command, “Tactical Mission Report, Mission No. 40 Flown 10 March 1945,”n.d., Secret

Source: Library of Congress, Curtis LeMay Papers, Box B-36

As part of the war with Japan, the Army Air Force waged a campaign to destroy major industrial centers with incendiary bombs. This document is General Curtis LeMay’s report on the firebombing of Tokyo--“the most destructive air raid in history”--which burned down over 16 square miles of the city, killed up to 100,000 civilians (the official figure was 83,793), injured more than 40,000, and made over 1 million homeless.  [13]  According to the “Foreword,” the purpose of the raid, which dropped 1,665 tons of incendiary bombs, was to destroy industrial and strategic targets “ not  to bomb indiscriminately civilian populations.” Air Force planners, however, did not distinguish civilian workers from the industrial and strategic structures that they were trying to destroy.

The killing of workers in the urban-industrial sector was one of the explicit goals of the air campaign against Japanese cities. According to a Joint Chiefs of Staff report on Japanese target systems, expected results from the bombing campaign included: “The absorption of man-hours in repair and relief; the dislocation of labor by casualty; the interruption of public services necessary to production, and above all the destruction of factories engaged in war industry.” While Stimson would later raise questions about the bombing of Japanese cities, he was largely disengaged from the details (as he was with atomic targeting). [14]

Firebombing raids on other cities followed Tokyo, including Osaka, Kobe, Yokahama, and Nagoya, but with fewer casualties (many civilians had fled the cities). For some historians, the urban fire-bombing strategy facilitated atomic targeting by creating a “new moral context,” in which earlier proscriptions against intentional targeting of civilians had eroded. [15]

Document 9 : Notes on Initial Meeting of Target Committee, May 2, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5d (copy from microfilm)

On 27 April, military officers and nuclear scientists met to discuss bombing techniques, criteria for target selection, and overall mission requirements. The discussion of “available targets” included Hiroshima, the “largest untouched target not on the 21 st  Bomber Command priority list.” But other targets were under consideration, including Yawata (northern Kyushu), Yokohama, and Tokyo (even though it was practically “rubble.”) The problem was that the Air Force had a policy of “laying waste” to Japan’s cities which created tension with the objective of reserving some urban targets for nuclear destruction.  [16]

Document 10 : Memorandum from J. R. Oppenheimer to Brigadier General Farrell, May 11, 1945

Source: RG 77, MED Records, Top Secret Documents, File no. 5g (copy from microfilm)

As director of Los Alamos Laboratory, Oppenheimer’s priority was producing a deliverable bomb, but not so much the effects of the weapon on the people at the target. In keeping with General Groves’ emphasis on compartmentalization, the Manhattan Project experts on the effects of radiation on human biology were at the MetLab and other offices and had no interaction with the production and targeting units. In this short memorandum to Groves’ deputy, General Farrell, Oppenheimer explained the need for precautions because of the radiological dangers of a nuclear detonation. The initial radiation from the detonation would be fatal within a radius of about 6/10ths of a mile and “injurious” within a radius of a mile. The point was to keep the bombing mission crew safe; concern about radiation effects had no impact on targeting decisions.  [17]

Document 11 : Memorandum from Major J. A. Derry and Dr. N.F. Ramsey to General L.R. Groves, “Summary of Target Committee Meetings on 10 and 11 May 1945,” May 12, 1945, Top Secret

Scientists and officers held further discussion of bombing mission requirements, including height of detonation, weather, radiation effects (Oppenheimer’s memo), plans for possible mission abort, and the various aspects of target selection, including priority cities (“a large urban area of more than three miles diameter”) and psychological dimension. As for target cities, the committee agreed that the following should be exempt from Army Air Force bombing so they would be available for nuclear targeting: Kyoto, Hiroshima, Yokohama, and Kokura Arsenal. Japan’s cultural capital, Kyoto, would not stay on the list. Pressure from Secretary of War Stimson had already taken Kyoto off the list of targets for incendiary bombings and he would successfully object to the atomic bombing of that city.  [18]

Document 12 : Stimson Diary Entries, May 14 and 15, 1945

Source: Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

On May 14 and 15, Stimson had several conversations involving S-1 (the atomic bomb); during a talk with Assistant Secretary of War John J. McCloy, he estimated that possession of the bomb gave Washington a tremendous advantage—“held all the cards,” a “royal straight flush”-- in dealing with Moscow on post-war problems: “They can’t get along without our help and industries and we have coming into action a weapon which will be unique.” The next day a discussion of divergences with Moscow over the Far East made Stimson wonder whether the atomic bomb would be ready when Truman met with Stalin in July. If it was, he believed that the bomb would be the “master card” in U.S. diplomacy. This and other entries from the Stimson diary (as well as the entry from the Davies diary that follows) are important to arguments developed by Gar Alperovitz and Barton J. Bernstein, among others, although with significantly different emphases, that in light of controversies with the Soviet Union over Eastern Europe and other areas, top officials in the Truman administration believed that possessing the atomic bomb would provide them with significant leverage for inducing Moscow’s acquiescence in U.S. objectives. [19]

Document 13 : Davies Diary entry for May 21, 1945

Source: Joseph E. Davies Papers, Library of Congress, box 17, 21 May 1945

While officials at the Pentagon continued to look closely at the problem of atomic targets, President Truman, like Stimson, was thinking about the diplomatic implications of the bomb. During a conversation with Joseph E. Davies, a prominent Washington lawyer and former ambassador to the Soviet Union, Truman said that he wanted to delay talks with Stalin and Churchill until July when the first atomic device had been tested. Alperovitz treated this entry as evidence in support of the atomic diplomacy argument, but other historians, ranging from Robert Maddox to Gabriel Kolko, have denied that the timing of the Potsdam conference had anything to do with the goal of using the bomb to intimidate the Soviets. [20]

Document 14 : Letter, O. C. Brewster to President Truman, 24 May 1945, with note from Stimson to Marshall, 30 May 1945, attached, secret

Source: Harrison-Bundy Files relating to the Development of the Atomic Bomb, 1942-1946, microfilm publication M1108 (Washington, D.C.: National Archives and Records Administration, 1980), File 77: "Interim Committee - International Control."

In what Stimson called the “letter of an honest man,” Oswald C. Brewster sent President Truman a profound analysis of the danger and unfeasibility of a U.S. atomic monopoly.  [21]  An engineer for the Kellex Corporation, which was involved in the gas diffusion project to enrich uranium, Brewster recognized that the objective was fissile material for a weapon. That goal, he feared, raised terrifying prospects with implications for the “inevitable destruction of our present day civilization.” Once the U.S. had used the bomb in combat other great powers would not tolerate a monopoly by any nation and the sole possessor would be “be the most hated and feared nation on earth.” Even the U.S.’s closest allies would want the bomb because “how could they know where our friendship might be five, ten, or twenty years hence.” Nuclear proliferation and arms races would be certain unless the U.S. worked toward international supervision and inspection of nuclear plants.

Brewster suggested that Japan could be used as a “target” for a “demonstration” of the bomb, which he did not further define. His implicit preference, however, was for non-use; he wrote that it would be better to take U.S. casualties in “conquering Japan” than “to bring upon the world the tragedy of unrestrained competitive production of this material.”

Document 15 : Minutes of Third Target Committee Meeting – Washington, May 28, 1945, Top Secret

More updates on training missions, target selection, and conditions required for successful detonation over the target. The target would be a city--either Hiroshima, Kyoto (still on the list), or Niigata--but specific “aiming points” would not be specified at that time nor would industrial “pin point” targets because they were likely to be on the “fringes” a city. The bomb would be dropped in the city’s center. “Pumpkins” referred to bright orange, pumpkin-shaped high explosive bombs—shaped like the “Fat Man” implosion weapon--used for bombing run test missions.

Document 16 : General Lauris Norstad to Commanding General, XXI Bomber Command, “509 th  Composite Group; Special Functions,” May 29, 1945, Top Secret

The 509 th  Composite Group’s cover story for its secret mission was the preparation of “Pumpkins” for use in battle. In this memorandum, Norstad reviewed the complex requirements for preparing B-29s and their crew for successful nuclear strikes.

Document 17 : Assistant Secretary of War John J. McCloy, “Memorandum of Conversation with General Marshal May 29, 1945 – 11:45 p.m.,” Top Secret

Source: Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 12, S-1

Tacitly dissenting from the Targeting Committee’s recommendations, Army Chief of Staff George Marshall argued for initial nuclear use against a clear-cut military target such as a “large naval installation.” If that did not work, manufacturing areas could be targeted, but only after warning their inhabitants. Marshall noted the “opprobrium which might follow from an ill considered employment of such force.” This document has played a role in arguments developed by Barton J. Bernstein that figures such as Marshall and Stimson were “caught between an older morality that opposed the intentional killing of non-combatants and a newer one that stressed virtually total war.” [22]  

Document 18 : “Notes of the Interim Committee Meeting Thursday, 31 May 1945, 10:00 A.M. to 1:15 P.M. – 2:15 P.M. to 4:15 P.M., ” n.d., Top Secret

Source: RG 77, MED Records, H-B files, folder no. 100 (copy from microfilm)

With Secretary of War Stimson presiding, members of the committee heard reports on a variety of Manhattan Project issues, including the stages of development of the atomic project, problems of secrecy, the possibility of informing the Soviet Union, cooperation with “like-minded” powers, the military impact of the bomb on Japan, and the problem of “undesirable scientists.” Interested in producing the “greatest psychological effect,” the Committee members agreed that the “most desirable target would be a vital war plant employing a large number of workers and closely surrounded by workers’ houses.” Exactly how the mass deaths of civilians would persuade Japanese rulers to surrender was not discussed. Bernstein has argued that this target choice represented an uneasy endorsement of “terror bombing”--the target was not exclusively military or civilian; nevertheless, worker’s housing would include non-combatant men, women, and children. [23]  It is possible that Truman was informed of such discussions and their conclusions, although he clung to a belief that the prospective targets were strictly military.

Document 19 : General George A. Lincoln to General Hull, June 4, 1945, enclosing draft, Top Secret

Source: Record Group 165, Records of the War Department General and Special Staffs, American-British-Canadian Top Secret Correspondence, Box 504, “ABC 387 Japan (15 Feb. 45)

George A. Lincoln, chief of the Strategy and Policy Group at U.S. Army’s Operations Department, commented on a memorandum by former President Herbert Hoover that Stimson had passed on for analysis. Hoover proposed a compromise solution with Japan that would allow Tokyo to retain part of its empire in East Asia (including Korea and Japan) as a way to head off Soviet influence in the region. While Lincoln believed that the proposed peace teams were militarily acceptable he doubted that they were workable or that they could check Soviet “expansion” which he saw as an inescapable result of World War II. As to how the war with Japan would end, he saw it as “unpredictable,” but speculated that “it will take Russian entry into the war, combined with a landing, or imminent threat of a landing, on Japan proper by us, to convince them of the hopelessness of their situation.” Lincoln derided Hoover’s casualty estimate of 500,000. J. Samuel Walker has cited this document to make the point that “contrary to revisionist assertions, American policymakers in the summer of 1945 were far from certain that the Soviet invasion of Manchuria would be enough in itself to force a Japanese surrender.”  [24]

Document 20 : Memorandum from R. Gordon Arneson, Interim Committee Secretary, to Mr. Harrison, June 6, 1945, Top Secret

In a memorandum to George Harrison, Stimson’s special assistant on Manhattan Project matters, Arneson noted actions taken at the recent Interim Committee meetings, including target criterion and an attack “without prior warning.”

Document 21 : Memorandum of Conference with the President, June 6, 1945, Top Secret

Source: Henry Stimson Papers, Sterling Library, Yale University (microfilm at Library of Congress)

Stimson and Truman began this meeting by discussing how they should handle a conflict with French President DeGaulle over the movement by French forces into Italian territory. (Truman finally cut off military aid to France to compel the French to pull back).  [25]  As evident from the discussion, Stimson strongly disliked de Gaulle whom he regarded as “psychopathic.” The conversation soon turned to the atomic bomb, with some discussion about plans to inform the Soviets but only after a successful test. Both agreed that the possibility of a nuclear “partnership” with Moscow would depend on “quid pro quos”: “the settlement of the Polish, Rumanian, Yugoslavian, and Manchurian problems.”

At the end, Stimson shared his doubts about targeting cities and killing civilians through area bombing because of its impact on the U.S.’s reputation as well as on the problem of finding targets for the atomic bomb. Barton Bernstein has also pointed to this as additional evidence of the influence on Stimson of an “an older morality.” While concerned about the U.S.’s reputation, Stimson did not want the Air Force to bomb Japanese cities so thoroughly that the “new weapon would not have a fair background to show its strength,” a comment that made Truman laugh.  The discussion of “area bombing” may have reminded him that Japanese civilians remained at risk from U.S. bombing operations.

III. Debates on Alternatives to First Use and Unconditional Surrender

Document 22 : Memorandum from Arthur B. Compton to the Secretary of War, enclosing “Memorandum on `Political and Social Problems,’ from Members of the `Metallurgical Laboratory’ of the University of Chicago,” June 12, 1945, Secret

Source: RG 77, MED Records, H-B files, folder no. 76 (copy from microfilm)

Physicists Leo Szilard and James Franck, a Nobel Prize winner, were on the staff of the “Metallurgical Laboratory” at the University of Chicago, a cover for the Manhattan Project program to produce fuel for the bomb. The outspoken Szilard was not involved in operational work on the bomb and General Groves kept him under surveillance but Met Lab director Arthur Compton found Szilard useful to have around. Concerned with the long-run implications of the bomb, Franck chaired a committee, in which Szilard and Eugene Rabinowitch were major contributors, that produced a report rejecting a surprise attack on Japan and recommended instead a demonstration of the bomb on the “desert or a barren island.” Arguing that a nuclear arms race “will be on in earnest not later than the morning after our first demonstration of the existence of nuclear weapons,” the committee saw international control as the alternative. That possibility would be difficult if the United States made first military use of the weapon. Compton raised doubts about the recommendations but urged Stimson to study the report. Martin Sherwin has argued that the Franck committee shared an important assumption with Truman et al.--that an “atomic attack against Japan would `shock’ the Russians”--but drew entirely different conclusions about the import of such a shock.  [26]

Document 23 : Memorandum from Acting Secretary of State Joseph Grew to the President, “Analysis of Memorandum Presented by Mr. Hoover,” June 13, 1945

Source: Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 8, Japan (After December 7/41)

A former ambassador to Japan, Joseph Grew’s extensive knowledge of Japanese politics and culture informed his stance toward the concept of unconditional surrender. He believed it essential that the United States declare its intention to preserve the institution of the emperor. As he argued in this memorandum to President Truman, “failure on our part to clarify our intentions” on the status of the emperor “will insure prolongation of the war and cost a large number of human lives.” Documents like this have played a role in arguments developed by Alperovitz that Truman and his advisers had alternatives to using the bomb such as modifying unconditional surrender and that anti-Soviet considerations weighed most heavily in their thinking. By contrast, Herbert P. Bix has suggested that the Japanese leadership would “probably not” have surrendered if the Truman administration had spelled out the status of the emperor. [27]

Document 24 : Memorandum from Chief of Staff Marshall to the Secretary of War, 15 June 1945, enclosing “Memorandum of Comments on `Ending the Japanese War,’” prepared by George A. Lincoln, June 14, 1945, Top Secret

Commenting on another memorandum by Herbert Hoover, George A. Lincoln discussed war aims, face-saving proposals for Japan, and the nature of the proposed declaration to the Japanese government, including the problem of defining “unconditional surrender.” Lincoln argued against modifying the concept of unconditional surrender: if it is “phrased so as to invite negotiation” he saw risks of prolonging the war or a “compromise peace.” J. Samuel Walker has observed that those risks help explain why senior officials were unwilling to modify the demand for unconditional surrender. [28]

Document 25 : Memorandum by J. R. Oppenheimer, “Recommendations on the Immediate Use of Nuclear Weapons,” June 16, 1945, Top Secret

In a report to Stimson, Oppenheimer and colleagues on the scientific advisory panel--Arthur Compton, Ernest O. Lawrence, and Enrico Fermi—tacitly disagreed with the report of the “Met Lab” scientists. The panel argued for early military use but not before informing key allies about the atomic project to open a dialogue on “how we can cooperate in making this development contribute to improved international relations.”

Document 26 : “Minutes of Meeting Held at the White House on Monday, 18 June 1945 at 1530,” Top Secret

Source: Record Group 218, Records of the Joint Chiefs of Staff, Central Decimal Files, 1942-1945, box 198 334 JCS (2-2-45) Mtg 186 th -194 th

With the devastating battle for Okinawa winding up, Truman and the Joint Chiefs stepped back and considered what it would take to secure Japan’s surrender. The discussion depicted a Japan that, by 1 November, would be close to defeat, with great destruction and economic losses produced by aerial bombing and naval blockade, but not ready to capitulate. Marshall believed that the latter required Soviet entry and an invasion of Kyushu, even suggesting that Soviet entry might be the “decisive action levering them into capitulation.” Truman and the Chiefs reviewed plans to land troops on Kyushu on 1 November, which Marshall believed was essential because air power was not decisive. He believed that casualties would not be more than those produced by the battle for Luzon, some 31,000. This account hints at discussion of the atomic bomb (“certain other matters”), but no documents disclose that part of the meeting.

The record of this meeting has figured in the complex debate over the estimates of casualties stemming from a possible invasion of Japan. While post-war justifications for the bomb suggested that an invasion of Japan could have produced very high levels of casualties (dead, wounded, or missing), from hundreds of thousands to a million, historians have vigorously debated the extent to which the estimates were inflated.  [29]

According to accounts based on post-war recollections and interviews, during the meeting McCloy raised the possibility of winding up the war by guaranteeing the preservation of the emperor albeit as a constitutional monarch. If that failed to persuade Tokyo, he proposed that the United States disclose the secret of the atomic bomb to secure Japan’s unconditional surrender. While McCloy later recalled that Truman expressed interest, he said that Secretary of State Byrnes squashed the proposal because of his opposition to any “deals” with Japan. Yet, according to Forrest Pogue’s account, when Truman asked McCloy if he had any comments, the latter opened up a discussion of nuclear weapons use by asking “Why not use the bomb?” [30]

Document 27 : Memorandum from R. Gordon Arneson, Interim Committee Secretary, to Mr. Harrison, June 25, 1945, Top Secret

For Harrison’s convenience, Arneson summarized key decisions made at the 21 June meeting of the Interim Committee, including a recommendation that President Truman use the forthcoming conference of allied leaders to inform Stalin about the atomic project. The Committee also reaffirmed earlier recommendations about the use of the bomb at the “earliest opportunity” against “dual targets.” In addition, Arneson included the Committee’s recommendation for revoking part two of the 1944 Quebec agreement which stipulated that the neither the United States nor Great Britain would use the bomb “against third parties without each other’s consent.” Thus, an impulse for unilateral control of nuclear use decisions predated the first use of the bomb.

Document 28 : Memorandum from George L. Harrison to Secretary of War, June 26, 1945, Top Secret

Source: RG 77, MED, H-B files, folder no. 77 (copy from microfilm)

Reminding Stimson about the objections of some Manhattan project scientists to military use of the bomb, Harrison summarized the basic arguments of the Franck report. One recommendation shared by many of the scientists, whether they supported the report or not, was that the United States inform Stalin of the bomb before it was used. This proposal had been the subject of positive discussion by the Interim Committee on the grounds that Soviet confidence was necessary to make possible post-war cooperation on atomic energy.

Document 29 : Memorandum from George L. Harrison to Secretary of War, June 28, 1945, Top Secret, enclosing Ralph Bard’s “Memorandum on the Use of S-1 Bomb,” June 27, 1945

Under Secretary of the Navy Ralph Bard joined those scientists who sought to avoid military use of the bomb; he proposed a “preliminary warning” so that the United States would retain its position as a “great humanitarian nation.” Alperovitz cites evidence that Bard discussed his proposal with Truman who told him that he had already thoroughly examined the problem of advanced warning. This document has also figured in the argument framed by Barton Bernstein that Truman and his advisers took it for granted that the bomb was a legitimate weapon and that there was no reason to explore alternatives to military use. Bernstein, however, notes that Bard later denied that he had a meeting with Truman and that White House appointment logs support that claim. [31]

Document 30 : Memorandum for Mr. McCloy, “Comments re: Proposed Program for Japan,” June 28, 1945, Draft, Top Secret

Source: RG 107, Office of Assistant Secretary of War Formerly Classified Correspondence of John J. McCloy, 1941-1945, box 38, ASW 387 Japan

Despite the interest of some senior officials such as Joseph Grew, Henry Stimson, and John J. McCloy in modifying the concept of unconditional surrender so that the Japanese could be sure that the emperor would be preserved, it remained a highly contentious subject. For example, one of McCloy’s aides, Colonel Fahey, argued against modification of unconditional surrender (see “Appendix ‘C`”).

Document 31 : Assistant Secretary of War John J. McCloy to Colonel Stimson, June 29, 1945, Top Secret

McCloy was part of a drafting committee at work on the text of a proclamation to Japan to be signed by heads of state at the forthcoming Potsdam conference. As McCloy observed the most contentious issue was whether the proclamation should include language about the preservation of the emperor: “This may cause repercussions at home but without it those who seem to know the most about Japan feel there would be very little likelihood of acceptance.”

Document 32 : Memorandum, “Timing of Proposed Demand for Japanese Surrender,” June 29, 1945, Top Secret

Probably the work of General George A. Lincoln at Army Operations, this document was prepared a few weeks before the Potsdam conference when senior officials were starting to finalize the text of the declaration that Truman, Churchill, and Chiang would issue there. The author recommended issuing the declaration “just before the bombardment program [against Japan] reaches its peak.” Next to that suggestion, Stimson or someone in his immediate office, wrote “S1”, implying that the atomic bombing of Japanese cities was highly relevant to the timing issue. Also relevant to Japanese thinking about surrender, the author speculated, was the Soviet attack on their forces after a declaration of war.

Document 33 : Stimson memorandum to The President, “Proposed Program for Japan,” 2 July 1945, Top Secret

Source: Naval Aide to the President Files, box 4, Berlin Conference File, Volume XI - Miscellaneous papers: Japan, Harry S. Truman Presidential Library

On 2 July Stimson presented to President Truman a proposal that he had worked up with colleagues in the War Department, including McCloy, Marshall, and Grew. The proposal has been characterized as “the most comprehensive attempt by any American policymaker to leverage diplomacy” in order to shorten the Pacific War. Stimson had in mind a “carefully timed warning” delivered before the invasion of Japan. Some of the key elements of Stimson’s argument were his assumption that “Japan is susceptible to reason” and that Japanese might be even more inclined to surrender if “we do not exclude a constitutional monarchy under her present dynasty.” The possibility of a Soviet attack would be part of the “threat.” As part of the threat message, Stimson alluded to the “inevitability and completeness of the destruction” which Japan could suffer, but he did not make it clear whether unconditional surrender terms should be clarified before using the atomic bomb. Truman read Stimson’s proposal, which he said was “powerful,” but made no commitments to the details, e.g., the position of the emperor.  [32]

Document 34 : Minutes, Secretary’s Staff Committee, Saturday Morning, July 7, 1945, 133d Meeting, Top Secret

Source: Record Group 353, Records of Interdepartmental and Intradepartmental Committees, Secretary’s Staff Meetings Minutes, 1944-1947 (copy from microfilm)

The possibility of modifying the concept of unconditional surrender so that it guaranteed the continuation of the emperor remained hotly contested within the U.S. government. Here senior State Department officials, Under Secretary Joseph Grew on one side, and Assistant Secretary Dean Acheson and Archibald MacLeish on the other, engaged in hot debate.

Document 35 : Combined Chiefs of Staff, “Estimate of the Enemy Situation (as of 6 July 1945, C.C.S 643/3, July 8, 1945, Secret (Appendices Not Included)

Source: RG 218, Central Decimal Files, 1943-1945, CCS 381 (6-4-45), Sec. 2 Pt. 5

This review of Japanese capabilities and intentions portrays an economy and society under “tremendous strain”; nevertheless, “the ground component of the Japanese armed forces remains Japan’s greatest military asset.” Alperovitz sees statements in this estimate about the impact of Soviet entry into the war and the possibility of a conditional surrender involving survival of the emperor as an institution as more evidence that the policymakers saw alternatives to nuclear weapons use. By contrast, Richard Frank takes note of the estimate’s depiction of the Japanese army’s terms for peace: “for surrender to be acceptable to the Japanese army it would be necessary for the military leaders to believe that it would not entail discrediting the warrior tradition and that it would permit the ultimate resurgence of a military in Japan.” That, Frank argues, would have been “unacceptable to any Allied policy maker.” [33]

Document 36 : Cable to Secretary of State from Acting Secretary Joseph Grew, July 16, 1945, Top Secret

Source: Record Group 59, Decimal Files 1945-1949, 740.0011 PW (PE)/7-1645

On the eve of the Potsdam Conference, a State Department draft of the proclamation to Japan contained language which modified unconditional surrender by promising to retain the emperor. When former Secretary of State Cordell Hull learned about it he outlined his objections to Byrnes, arguing that it might be better to wait “the climax of allied bombing and Russia’s entry into the war.” Byrnes was already inclined to reject that part of the draft, but Hull’s argument may have reinforced his decision.

Document 37 : Letter from Stimson to Byrnes, enclosing memorandum to the President, “The Conduct of the War with Japan,” 16 July 1945, Top Secret

Source: Henry L. Stimson Papers (MS 465), Sterling Library, Yale University (reel 113) (microfilm at Library of Congress)

Still interested in trying to find ways to “warn Japan into surrender,” this represents an attempt by Stimson before the Potsdam conference, to persuade Truman and Byrnes to agree to issue warnings to Japan prior to the use of the bomb. The warning would draw on the draft State-War proclamation to Japan; presumably, the one criticized by Hull (above) which included language about the emperor .  Presumably the clarified warning would be issued prior to the use of the bomb; if the Japanese persisted in fighting then “the full force of our new weapons should be brought to bear” and a “heavier” warning would be issued backed by the “actual entrance of the Russians in the war.” Possibly, as Malloy has argued, Stimson was motivated by concerns about using the bomb against civilians and cities, but his latest proposal would meet resistance at Potsdam from Byrnes and other. [34]

Document 38 : R. E. Lapp, Leo Szilard et al., “A Petition to the President of the United States,” July 17, 1945

On the eve of the Potsdam conference, Leo Szilard circulated a petition as part of a final effort to discourage military use of the bomb. Signed by about 68 Manhattan Project scientists, mainly physicists and biologists (copies with the remaining signatures are in the archival file), the petition did not explicitly reject military use, but raised questions about an arms race that military use could instigate and requested Truman to publicize detailed terms for Japanese surrender. Truman, already on his way to Europe, never saw the petition. [35]

IV. The Japanese Search for Soviet Mediation

Documents 39A-B: Magic

39A : William F. Friedman, Consultant (Armed Forces Security Agency), “A Short History of U.S. COMINT Activities,” 19 February 1952, Top Secret

39B :“Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1204 – July 12, 1945, Top Secret Ultra

Sources: A: National Security Agency Mandatory declassification review release; B: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

Beginning in September 1940, U.S. military intelligence began to decrypt routinely, under the “Purple” code-name, the intercepted cable traffic of the Japanese Foreign Ministry. Collectively the decoded messages were known as “Magic.” How this came about is explained in an internal history of pre-war and World War II Army and Navy code-breaking activities prepared by  William F. Friedman , a central figure in the development of U.S. government cryptology during the 20 th  century. The National Security Agency kept the ‘Magic” diplomatic and military summaries classified for many years and did not release the entire series for 1942 through August 1945 until the early 1990s. [36]

The 12 July 1945 “Magic” summary includes a report on a cable from Japanese Foreign Minister Shigenori Togo to Ambassador Naotake Sato in Moscow concerning the Emperor’s decision to seek Soviet help in ending the war. Not knowing that the Soviets had already made a commitment to their Allies to declare war on Japan, Tokyo fruitlessly pursued this option for several weeks. The “Magic” intercepts from mid-July have figured in Gar Alperovitz’s argument that Truman and his advisers recognized that the Emperor was ready to capitulate if the Allies showed more flexibility on the demand for unconditional surrender. This point is central to Alperovitz’s thesis that top U.S. officials recognized a “two-step logic”: relaxing unconditional surrender and a Soviet declaration of war would have been enough to induce Japan’s surrender without the use of the bomb. [37]

Document 40 : John Weckerling, Deputy Assistant Chief of Staff, G-2, July 12, 1945, to Deputy Chief of Staff, “Japanese Peace Offer,” 13 July 1945, Top Secret Ultra

Source: RG 165, Army Operations OPD Executive File #17, Item 13 (copy courtesy of J. Samuel Walker)

The day after the Togo message was reported, Army intelligence chief Weckerling proposed several possible explanations of the Japanese diplomatic initiative. Robert J. Maddox has cited this document to support his argument that top U.S. officials recognized that Japan was not close to surrender because Japan was trying to “stave off defeat.” In a close analysis of this document, Tsuyoshi Hasegawa, who is also skeptical of claims that the Japanese had decided to surrender, argues that each of the three possibilities proposed by Weckerling “contained an element of truth, but none was entirely correct”. For example, the “governing clique” that supported the peace moves was not trying to “stave off defeat” but was seeking Soviet help to end the war. [38]

Document 41 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1205 – July 13, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

The day after he told Sato about the current thinking on Soviet mediation, Togo requested the Ambassador to see Soviet Foreign Minister Vyacheslav Molotov and tell him of the Emperor’s “private intention to send Prince Konoye as a Special Envoy” to Moscow. Before he received Togo’s message, Sato had already met with Molotov on another matter.

Document 42 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1210 – July 17, 1945, Top Secret Ultra

Source: Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

Another intercept of a cable from Togo to Sato shows that the Foreign Minister rejected unconditional surrender and that the Emperor was not “asking the Russian’s mediation in anything like unconditional surrender.” Incidentally, this “`Magic’ Diplomatic Summary” indicates the broad scope and capabilities of the program; for example, it includes translations of intercepted French messages (see pages 8-9).

Document 43 : Admiral Tagaki Diary Entry for July 20, 1945

Source: Takashi Itoh, ed.,  Sokichi Takagi: Nikki to Joho  [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 916-917 [Translation by Hikaru Tajima]

In 1944 Navy minister Mitsumasa Yonai ordered rear admiral Sokichi Takagi to go on sick leave so that he could undertake a secret mission to find a way to end the war. Tagaki was soon at the center of a cabal of Japanese defense officials, civil servants, and academics, which concluded that, in the end, the emperor would have to “impose his decision on the military and the government.” Takagi kept a detailed account of his activities, part of which was in diary form, the other part of which he kept on index cards. The material reproduced here gives a sense of the state of play of Foreign Minister Togo’s attempt to secure Soviet mediation. Hasegawa cited it and other documents to make a larger point about the inability of the Japanese government to agree on “concrete” proposals to negotiate an end to the war. [39]

The last item discusses Japanese contacts with representatives of the Office of Strategic Services (OSS) in Switzerland. The reference to “our contact” may refer to Bank of International Settlements economist Pers Jacobbson who was in touch with Japanese representatives to the Bank as well as Gero von Gävernitz, then on the staff, but with non-official cover, of OSS station chief Allen Dulles. The contacts never went far and Dulles never received encouragement to pursue them. [40]

V. The Trinity Test

Document 44 : Letter from Commissar of State Security First Rank, V. Merkulov, to People’s Commissar for Internal Affairs L. P. Beria, 10 July 1945, Number 4305/m, Top Secret (translation by Anna Melyaskova)

Source:  L.D. Riabev, ed.,  Atomnyi Proekt SSSR  (Moscow: izd MFTI, 2002), Volume 1, Part 2, 335-336

This 10 July 1945 letter from NKVD director V. N. Merkulov to Beria is an example of Soviet efforts to collect inside information on the Manhattan Project, although not all the detail was accurate. Merkulov reported that the United States had scheduled the test of a nuclear device for that same day, although the actual test took place 6 days later. According to Merkulov, two fissile materials were being produced: element-49 (plutonium), and U-235; the test device was fueled by plutonium. The Soviet source reported that the weight of the device was 3 tons (which was in the ball park) and forecast an explosive yield of 5 kilotons. That figure was based on underestimates by Manhattan Project scientists: the actual yield of the test device was 20 kilotons.

As indicated by the L.D. Riabev’s notes, it is possible that Beria’s copy of this letter ended up in Stalin’s papers. That the original copy is missing from Beria’s papers suggests that he may have passed it on to Stalin before the latter left for the Potsdam conference. [41]

Document 45 : Telegram War [Department] 33556, from Harrison to Secretary of War, July 17, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File 5e (copy from microfilm)

An elated message from Harrison to Stimson reported the success of the  Trinity Test  of a plutonium implosion weapon. The light from the explosion could been seen “from here [Washington, D.C.] to “high hold” [Stimson’s estate on Long Island—250 miles away]” and it was so loud that Harrison could have heard the “screams” from Washington, D.C. to “my farm” [in Upperville, VA, 50 miles away] [42]

Document 46 : Memorandum from General L. R. Groves to Secretary of War, “The Test,” July 18, 1945, Top Secret, Excised Copy

Source: RG 77, MED Records, Top Secret Documents, File no. 4 (copy from microfilm)

General Groves prepared for Stimson, then at Potsdam, a detailed account of the Trinity test. [43]

VI. The Potsdam Conference

Document 47 : Truman’s Potsdam Diary

Source: Barton J. Bernstein, “Truman at Potsdam: His Secret Diary,”  Foreign Service Journal , July/August 1980, excerpts, used with author’s permission. [44]

Some years after Truman’s death, a hand-written diary that he kept during the Potsdam conference surfaced in his personal papers. For convenience, Barton Bernstein’s rendition is provided here but linked here are the scanned versions of Truman’s handwriting on the National Archives’ website (for 15-30 July).

The diary entries cover July 16, 17, 18, 20, 25, 26, and 30 and include Truman’s thinking about a number of issues and developments, including his reactions to Churchill and Stalin, the atomic bomb and how it should be targeted, the possible impact of the bomb and a Soviet declaration of war on Japan, and his decision to tell Stalin about the bomb. Receptive to pressure from Stimson, Truman recorded his decision to take Japan’s “old capital” (Kyoto) off the atomic bomb target list. Barton Bernstein and Richard Frank, among others, have argued that Truman’s assertion that the atomic targets were “military objectives” suggested that either he did not understand the power of the new weapons or had simply deceived himself about the nature of the targets. Another statement—“Fini Japs when that [Soviet entry] comes about”—has also been the subject of controversy over whether it meant that Truman thought it possible that the war could end without an invasion of Japan. [45]

Document 48 : Stimson Diary entries for July 16 through 25, 1945

Stimson did not always have Truman’s ear, but historians have frequently cited his diary when he was at the Potsdam conference. There Stimson kept track of S-1 developments, including news of the successful first test (see entry for July 16) and the ongoing deployments for nuclear use against Japan. When Truman received a detailed account of the test, Stimson reported that the “President was tremendously pepped up by it” and that “it gave him an entirely new feeling of confidence” (see entry for July 21). Whether this meant that Truman was getting ready for a confrontation with Stalin over Eastern Europe and other matters has also been the subject of debate.

An important question that Stimson discussed with Marshall, at Truman’s request, was whether Soviet entry into the war remained necessary to secure Tokyo’s surrender. Marshall was not sure whether that was so although Stimson privately believed that the atomic bomb would provide enough to force surrender (see entry for July 23). This entry has been cited by all sides of the controversy over whether Truman was trying to keep the Soviets out of the war. [46]  During the meeting on August 24, discussed above, Stimson gave his reasons for taking Kyoto off the atomic target list: destroying that city would have caused such “bitterness” that it could have become impossible “to reconcile the Japanese to us in that area rather than to the Russians.” Stimson vainly tried to preserve language in the Potsdam Declaration designed to assure the Japanese about “the continuance of their dynasty” but received Truman’s assurance that such a consideration could be conveyed later through diplomatic channels (see entry for July 24). Hasegawa argues that Truman realized that the Japanese would refuse a demand for unconditional surrender without a proviso on a constitutional monarchy and that “he needed Japan’s refusal to justify the use of the atomic bomb.” [47]

Document 49 : Walter Brown Diaries, July 10-August 3, 1945

Source: Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 10, folder 12, Byrnes, James F.: Potsdam, Minutes, July-August 1945

Walter Brown, who served as special assistant to Secretary of State Byrnes, kept a diary which provided considerable detail on the Potsdam conference and the growing concerns about Soviet policy among top U.S. officials. This document is a typed-up version of the hand-written original (which Brown’s family has provided to Clemson University). That there may be a difference between the two sources becomes evident from some of the entries; for example, in the entry for July 18, 1945 Brown wrote: "Although I knew about the atomic bomb when I wrote these notes, I dared not place it in writing in my book.”

The degree to which the typed-up version reflects the original is worth investigating. In any event, historians have used information from the diary to support various interpretations. For example, Bernstein cites the entries for 20 and 24 July to argue that “American leaders did not view Soviet entry as a substitute for the bomb” but that the latter “would be so powerful, and the Soviet presence in Manchuria so militarily significant, that there was no need for actual Soviet intervention in the war.” For  Brown's diary entry of 3 August 9 1945 historians have developed conflicting interpretations (See discussion of document 57). [48]

Document 50 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1214 – July 22, 1945, Top Secret Ultra

This “Magic” summary includes messages from both Togo and Sato. In a long and impassioned message, the latter argued why Japan must accept defeat: “it is meaningless to prove one’s devotion [to the Emperor] by wrecking the State.” Togo rejected Sato’s advice that Japan could accept unconditional surrender with one qualification: the “preservation of the Imperial House.” Probably unable or unwilling to take a soft position in an official cable, Togo declared that “the whole country … will pit itself against the enemy in accordance with the Imperial Will as long as the enemy demands unconditional surrender.”

Document 51 : Forrestal Diary Entry, July 24, 1945, “Japanese Peace Feelers”

Source: Naval Historical Center, Operational Archives, James Forrestal Diaries

Secretary of the Navy James Forrestal was a regular recipient of “Magic” intercept reports; this substantial entry reviews the dramatic Sato-Togo exchanges covered in the 22 July “Magic” summary (although Forrestal misdated Sato’s cable as “first of July” instead of the 21 st ). In contrast to Alperovitz’s argument that Forrestal tried to modify the terms of unconditional surrender to give the Japanese an out, Frank sees Forrestal’s account of the Sato-Togo exchange as additional evidence that senior U.S. officials understood that Tokyo was not on the “cusp of surrender.”  [49]

Document 52 : Davies Diary entry for July 29, 1945

S ource: Joseph E. Davies Papers, Library of Congress, Manuscripts Division, box 19, 29 July 1945

Having been asked by Truman to join the delegation to the Potsdam conference, former-Ambassador Davies sat at the table with the Big Three throughout the discussions. This diary entry has figured in the argument that Byrnes believed that the atomic bomb gave the United States a significant advantage in negotiations with the Soviet Union. Plainly Davies thought otherwise. [50]

VII. Debates among the Japanese – Late July/Early August 1945

Document 53 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1221- July 29, 1945, Top Secret Ultra

In the  Potsdam Declaration  the governments of China, Great Britain, and the United States) demanded the “unconditional surrender of all Japanese armed forces. “The alternative is prompt and utter destruction.” The next day, in response to questions from journalists about the government’s reaction to the ultimatum, Prime Minister Suzuki apparently said that “We can only ignore [ mokusatsu ] it. We will do our utmost to complete the war to the bitter end.” That, Bix argues, represents a “missed opportunity” to end the war and spare the Japanese from continued U.S. aerial attacks. [51]  Togo’s private position was more nuanced than Suzuki’s; he told Sato that “we are adopting a policy of careful study.” That Stalin had not signed the declaration (Truman and Churchill did not ask him to) led to questions about the Soviet attitude. Togo asked Sato to try to meet with Soviet Foreign Minister Molotov as soon as possible to “sound out the Russian attitude” on the declaration as well as Japan’s end-the-war initiative. Sato cabled Togo earlier that he saw no point in approaching the Soviets on ending the war until Tokyo had “concrete proposals.” “Any aid from the Soviets has now become extremely doubtful.”

Document 54 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1222 – July 30, 1945, Top Secret Ultra

This report included an intercept of a message from Sato reporting that it was impossible to see Molotov and that unless the Togo had a “concrete and definite plan for terminating the war” he saw no point in attempting to meet with him.

Document 55 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1225 – August 2, 1945, Top Secret Ultra

An intercepted message from Togo to Sato showed that Tokyo remained interested in securing Moscow’s good office but that it “is difficult to decide on concrete peace conditions here at home all at once.” “[W]e are exerting ourselves to collect the views of all quarters on the matter of concrete terms.” Barton Bernstein, Richard Frank, and Tsuyoshi Hasegawa, among others, have argued that the “Magic” intercepts from the end of July and early August show that the Japanese were far from ready to surrender. According to Herbert Bix, for months Hirohito had believed that the “outlook for a negotiated peace could be improved if Japan fought and won one last decisive battle,” thus, he delayed surrender, continuing to “procrastinate until the bomb was dropped and the Soviets attacked.” [52]

Document 56 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1226 - August 3, 1945, Top Secret Ultra

This summary included intercepts of Japanese diplomatic reporting on the Soviet buildup in the Far East as well as a naval intelligence report on Anglo-American discussions of U.S. plans for the invasion of Japan. Part II of the summary includes the rest of Togo’s 2 August cable which instructed Sato to do what he could to arrange an interview with Molotov.

Document 57 : Walter Brown Meeting Notes, August 3, 1945

Historians have used this item in the papers of Byrne’s aide, Walter Brown, to make a variety of points. Richard Frank sees this brief discussion of Japan’s interest in Soviet diplomatic assistance as crucial evidence that Admiral Leahy had been sharing “MAGIC” information with President Truman. He also points out that Truman and his colleagues had no idea what was behind Japanese peace moves, only that Suzuki had declared that he would “ignore” the Potsdam Declaration. Alperovitz, however, treats it as additional evidence that “strongly suggests” that Truman saw alternatives to using the bomb. [53]

Document 58 : “Magic” – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 502, 4 August 1945

Source: RG 457, Summaries of Intercepted Japanese Messages (“Magic” Far East Summary, March 20, 1942 – October 2, 1945), box 7, SRS 491-547

This “Far East Summary” included reports on the Japanese Army’s plans to disperse fuel stocks to reduce vulnerability to bombing attacks, the text of a directive by the commander of naval forces on “Operation Homeland,” the preparations and planning to repel a U.S. invasion of Honshu, and the specific identification of army divisions located in, or moving into, Kyushu. Both Richard Frank and Barton Bernstein have used intelligence reporting and analysis of the major buildup of Japanese forces on southern Kyushu to argue that U.S. military planners were so concerned about this development that by early August 1945 they were reconsidering their invasion plans. [54]

Document 59 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1228 – August 5, 1945, Top Secret Ultra

This summary included several intercepted messages from Sato, who conveyed his despair and exasperation over what he saw as Tokyo’s inability to develop terms for ending the war: “[I]f the Government and the Military dilly-dally in bringing this resolution to fruition, then all Japan will be reduced to ashes.” Sato remained skeptical that the Soviets would have any interest in discussions with Tokyo: “it is absolutely unthinkable that Russia would ignore the Three Power Proclamation and then engage in conversations with our special envoy.”

VIII. The Execution Order

Documents 60a-d: Framing the Directive for Nuclear Strikes:

60A . Cable VICTORY 213 from Marshall to Handy, July 22, 1945, Top Secret

60B . Memorandum from Colonel John Stone to General Arnold, “Groves Project,” 24 July 1945, Top Secret

60C . Cable WAR 37683 from General Handy to General Marshal, enclosing directive to General Spatz, July 24, 1945, Top Secret

60D . Cable VICTORY 261 from Marshall to General Handy, July 25, 1945, 25 July 1945, Top Secret

60E . General Thomas T. Handy to General Carl Spaatz, July 26, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, Files no. 5b and 5e ((copies from microfilm)

Top Army Air Force commanders may not have wanted to take responsibility for the first use of nuclear weapons on urban targets and sought formal authorization from Chief of Staff Marshall who was then in Potsdam. [55]  On 22 July Marshall asked Deputy Chief of Staff Thomas Handy to prepare a draft; General Groves wrote one which went to Potsdam for Marshall’s approval. Colonel John Stone, an assistant to commanding General of the Army Air Forces Henry H. “Hap” Arnold, had just returned from Potsdam and updated his boss on the plans as they had developed. On 25 July Marshall informed Handy that Secretary of War Stimson had approved the text; that same day, Handy signed off on a directive which ordered the use of atomic weapons on Japan, with the first weapon assigned to one of four possible targets—Hiroshima, Kokura, Niigata, or Nagasaki. “Additional bombs will be delivery on the [targets] as soon as made ready by the project staff.”

Document 61 : Memorandum from Major General L. R. Groves to Chief of Staff, July 30, 1945, Top Secret, Sanitized Copy

Source: RG 77, MED Records, Top Secret Documents, File no. 5

With more information on the Alamogordo test available, Groves provided Marshall with detail on the destructive power of atomic weapons. Barton J. Bernstein has observed that Groves’ recommendation that troops could move into the “immediate explosion area” within a half hour demonstrates the prevalent lack of top-level knowledge of the dangers of nuclear weapons effects. [56]  Groves also provided the schedule for the delivery of the weapons: the components of the gun-type bomb to be used on Hiroshima had arrived on Tinian, while the parts of the second weapon to be dropped were leaving San Francisco. By the end of November over ten weapons would be available, presumably in the event the war had continued.

Documents 62A-C: Weather delays

62A . CG 313 th  Bomb Wing, Tinian cable APCOM 5112 to War Department, August 3, 1945, Top Secret

62B . CG 313 th  Bomb Wing, Tinian cable APCOM 5130 to War Department, August 4, 1945, Top Secret

62C . CG 313 th  Bomb Wing, Tinian cable APCOM 5155 to War Department, August 4, 1945, Top Secret

Source: RG 77, Tinian Files, April-December 1945, box 21 (copies courtesy of Barton Bernstein)

The Hiroshima “operation” was originally slated to begin in early August depending on local conditions. As these cables indicate, reports of unfavorable weather delayed the plan. The second cable on 4 August shows that the schedule advanced to late in the evening of 5 August. The handwritten transcriptions are on the original archival copies.

IX. The First Nuclear Strikes and their Impact

Document 63 : Memorandum from General L. R. Groves to the Chief of Staff, August 6, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5b (copy from microfilm)

Two days after the bombing of Hiroshima, Groves provided Chief of Staff Marshall with a report which included messages from Captain William S. Parsons and others about the impact of the detonation which, through prompt radiation effects, fire storms, and blast effects, immediately killed at least 70,000, with many dying later from radiation sickness and other causes. [57]

How influential the atomic bombings of Hiroshima and later Nagasaki compared to the impact of the Soviet declaration of war were to the Japanese decision to surrender has been the subject of controversy among historians. Sadao Asada emphasizes the shock of the atomic bombs, while Herbert Bix has suggested that Hiroshima and the Soviet declaration of war made Hirohito and his court believe that failure to end the war could lead to the destruction of the imperial house. Frank and Hasegawa divide over the impact of the Soviet declaration of war, with Frank declaring that the Soviet intervention was “significant but not decisive” and Hasegawa arguing that the two atomic bombs “were not sufficient to change the direction of Japanese diplomacy. The Soviet invasion was.” [58]

Document 64 : Walter Brown Diary Entry, 6 August 1945

Source:  Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 68, folder 13, “Transcript/Draft B

Returning from the Potsdam Conference, sailing on the  U.S.S. Augusta , Truman learned about the atomic bombing of Hiroshima and announced it twice, first to those in the wardroom (socializing/dining area for commissioned officers), and then to the sailors’ mess. Still unaware of radiation effects, Truman emphasized the explosive yield. Later, he met with Secretary of State Byrnes and they discussed the Manhattan Project’s secrecy and the huge expenditures. Truman, who had been chair of the Senate Special Committee to Investigate the National Defense Program, said that “only on the appeal of Secretary of War Stimson did he refrain and let the War Department continue with the experiment unmolested.”

Document 65 : Directive from the Supreme Command Headquarters to the Commander-in-Chief of the Soviet Forces in the Far East on the Start of Combat Operations, No. 11122, Signed by [Communist Party General Secretary Joseph] Stalin and [Chief of General Staff A.I.] Antonov, 7 August 1945 (translation by Anna Melyakova)

Source: V. A. Zolotarev, ed.,  Sovetsko-Iaponskaia Voina 1945 Goda: Istoriia Voenno-Politicheskogo Protivoborstva Dvukh Derzhav v 30–40e Gody ( Moscow: Terra, 1997 and 2000), Vol. 7 (1), 340-341.

To keep his pledge at Yalta to enter the war against Japan and to secure the territorial concessions promised at the conference (e.g., Soviet annexation of the Kuriles and southern Sakhalin and a Soviet naval base at Port Arthur, etc.) Stalin considered various dates to schedule an attack. By early August he decided that 9-10 August 1945 would be the best dates for striking Japanese forces in Manchuria. In light of Japan’s efforts to seek Soviet mediation, Stalin wanted to enter the war quickly lest Tokyo reach a compromise peace with the Americans and the British at Moscow’s expense. But on 7 August, Stalin changed the instructions: the attack was to begin the next day. According to David Holloway, “it seems likely that the atomic bombing of Hiroshima the day before that impelled [Stalin] to speed up Soviet entry into the war” and “secure the gains promised at Yalta.” [59]

Document 66 : Memorandum of Conversation, “Atomic Bomb,” August 7, 1945

Source: Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945.

The Soviets already knew about the U.S. atomic project from espionage sources in the United States and Britain so Molotov’s comment to Ambassador Harriman about the secrecy surrounding the U.S. atomic project can be taken with a grain of salt, although the Soviets were probably unaware of specific plans for nuclear use.

Documents 67A-B:  Early High-level Reactions to the Hiroshima Bombing

67A : Cabinet Meeting and Togo's Meeting with the Emperor, August 7-8, 1945 Source: Gaimusho (Ministry of Foreign Affairs) ed.  Shusen Shiroku  (The Historical Records of the End of the War), annotated by Jun Eto, volume 4, 57-60 [Excerpts] [Translation by Toshihiro Higuchi]

67B : Admiral Tagaki Diary Entry for Wednesday, August 8 , 1945

Source: Takashi Itoh, ed.,  Sokichi Takagi: Nikki to Joho  [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 923-924 [Translation by Hikaru Tajima]

Excerpts from the Foreign Ministry's compilation about the end of the war show how news of the bombing reached Tokyo as well as how Foreign Minister's Togo initially reacted to reports about Hiroshima. When he learned of the atomic bombing from the Domei News Agency, Togo believed that it was time to give up and advised the cabinet that the atomic attack provided the occasion for Japan to surrender on the basis of the Potsdam Declaration. Togo could not persuade the cabinet, however, and the Army wanted to delay any decisions until it had learned what had happened to Hiroshima. When the Foreign Minister met with the Emperor, Hirohito agreed with him; he declared that the top priority was an early end to the war, although it would be acceptable to seek better surrender terms--probably U.S. acceptance of a figure-head emperor--if it did not interfere with that goal. In light of those instructions, Togo and Prime Minister Suzuki agreed that the Supreme War Council should meet the next day.  [59a]

An entry from Admiral Tagaki's diary for August 8 conveys more information on the mood in elite Japanese circles after Hiroshima, but before the Soviet declaration of war and the bombing of Nagasaki. Seeing the bombing of Hiroshima as a sign of a worsening situation at home, Tagaki worried about further deterioration. Nevertheless, his diary suggests that military hard-liners were very much in charge and that Prime Minister Suzuki was talking tough against surrender, by evoking last ditch moments in Japanese history and warning of the danger that subordinate commanders might not obey surrender orders. The last remark aggravated Navy Minister Yonai who saw it as irresponsible. That the Soviets had made no responses to Sato's request for a meeting was understood as a bad sign; Yonai realized that the government had to prepare for the possibility that Moscow might not help. One of the visitors mentioned at the beginning of the entry was Iwao Yamazaki who became Minister of the Interior in the next cabinet.

Document 68 : Navy Secretary James Forrestal to President Truman, August 8, 1945

General Douglas MacArthur had been slated as commander for military operations against Japan’s mainland, this letter to Truman from Forrestal shows that the latter believed that the matter was not settled. Richard Frank sees this as evidence of the uncertainty felt by senior officials about the situation in early August; Forrestal would not have been so “audacious” to take an action that could ignite a “political firestorm” if he “seriously thought the end of the war was near.”

Document 69 : Memorandum of Conversation, “Far Eastern War and General Situation,” August 8, 1945, Top Secret

Source: Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945

Shortly after the Soviets declared war on Japan, in line with commitments made at the Yalta and Potsdam conferences, Ambassador Harriman met with Stalin, with George Kennan keeping the U.S. record of the meeting. After Stalin reviewed in considerable detail, Soviet military gains in the Far East, they discussed the possible impact of the atomic bombing on Japan’s position (Nagasaki had not yet been attacked) and the dangers and difficulty of an atomic weapons program. According to Hasegawa, this was an important, even “startling,” conversation: it showed that Stalin “took the atomic bomb seriously”; moreover, he disclosed that the Soviets were working on their own atomic program. [60]

Document 70 : Entries for 8-9 August, Robert P. Meiklejohn Diary

Source: W.A. Harriman Papers, Library of Congress, box 211 , Robert Pickens Meiklejohn World War II Diary At London and Moscow March 10, 1941-February 14, 1946 , Volume II (Privately printed, 1980 [Printed from hand-written originals]) (Reproduced with permission)

Robert P. Meiklejohn, who worked as Ambassador W. A. Harriman’s administrative assistant at the U.S. Embassies in Moscow and London during and after World War II, kept a detailed diary of his experiences and observations. The entries for 8 and 9 August, prepared in light of the bombing of Hiroshima, include discussion of the British contribution to the Manhattan Project, Harriman (“his nibs’”) report on his meeting with Molotov about the Soviet declaration of war, and speculation about the impact of the bombing of Hiroshima on the Soviet decision. According to Meiklejohn, “None of us doubt that the atomic bomb speeded up the Soviets’ declaration of war.”

Document 71 : Memorandum of Conference with the President, August 8, 1945 at 10:45 AM

At their first meeting after the dropping of the bomb on Hiroshima, Stimson briefed Truman on the scale of the destruction, with Truman recognizing the “terrible responsibility” that was on his shoulders. Consistent with his earlier attempts, Stimson encouraged Truman to find ways to expedite Japan’s surrender by using “kindness and tact” and not treating them in the same way as the Germans. They also discussed postwar legislation on the atom and the pending Henry D. Smyth report on the scientific work underlying the Manhattan project and postwar domestic controls of the atom.

Documents 72A-C: The Attack on Nagasaki:

72A . Cable APCOM 5445 from General Farrell to O’Leary [Groves assistant], August 9, 1945, Top Secret

72B . COMGENAAF 8 cable CMDW 576 to COMGENUSASTAF, for General Farrell, August 9, 1945, Top secret

72C . COMGENAAF 20 Guam cable AIMCCR 5532 to COMGENUSASTAF Guam, August 10, 1945, Top Secret

Source: RG 77, Tinian Files, April-December 1945, box 20, Envelope G Tinian Files, Top Secret

The prime target for the second atomic attack was Kokura, which had a large army arsenal and ordnance works, but various problems ruled that city out; instead, the crew of the B-29 that carried “Fat Man” flew to an alternate target at Nagasaki. These cables are the earliest reports of the mission; the bombing of Nagasaki killed immediately at least 39,000 people, with more dying later. According to Frank, the “actual total of deaths due to the atomic bombs will never be known,” but the “huge number” ranges somewhere between 100,000 and 200,000 people. Barton J. Bernstein and Martin Sherwin have argued that if top Washington policymakers had kept tight control of the delivery of the bomb instead of delegating it to Groves the attack on Nagasaki could have been avoided. The combination of the first bomb and the Soviet declaration of war would have been enough to induce Tokyo’s surrender. By contrast, Maddox argues that Nagasaki was necessary so that Japanese “hardliners” could not “minimize the first explosion” or otherwise explain it away. [61]

Documents 73A-B: Ramsey Letter from Tinian Island

73A : Letter from Norman Ramsey to J. Robert Oppenheimer, undated [mid-August 1945], Secret, excerpts Source: Library of Congress, J. Robert Oppenheimer Papers, box 60, Ramsey, Norman

73B : Transcript of the letter prepared by editor.

Ramsey, a physicist, served as deputy director of the bomb delivery group, Project Alberta. This personal account, written on Tinian, reports his fears about the danger of a nuclear accident, the confusion surrounding the Nagasaki attack, and early Air Force thinking about a nuclear strike force.

X. Toward Surrender

Document 74 : “Magic” – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 507, August 9, 1945

Within days after the bombing of Hiroshima, U.S. military intelligence intercepted Japanese reports on the destruction of the city. According to an “Eyewitness Account (and Estimates Heard) … In Regard to the Bombing of Hiroshima”: “Casualties have been estimated at 100,000 persons.”

Document 75 : “Hoshina Memorandum” on the Emperor’s “Sacred Decision [ go-seidan] ,” 9-10 August, 1945

Source: Zenshiro Hoshina,  Daitoa Senso Hishi: Hoshina Zenshiro Kaiso-roku  [Secret History of the Greater East Asia War: Memoir of Zenshiro Hoshina] (Tokyo, Japan: Hara-Shobo, 1975), excerpts from Section 5, “The Emperor made  go-seidan  [= the sacred decision] – the decision to terminate the war,” 139-149 [translation by Hikaru Tajima]

Despite the bombing of Hiroshima, the Soviet declaration of war, and growing worry about domestic instability, the Japanese cabinet (whose decisions required unanimity) could not form a consensus to accept the Potsdam Declaration. Members of the Supreme War Council—“the Big Six” [62] —wanted the reply to Potsdam to include at least four conditions (e.g., no occupation, voluntary disarmament); they were willing to fight to the finish. The peace party, however, deftly maneuvered to break the stalemate by persuading a reluctant emperor to intervene. According to Hasegawa, Hirohito had become convinced that the preservation of the monarchy was at stake. Late in the evening of 9 August, the emperor and his advisers met in the bomb shelter of the Imperial Palace.

Zenshiro Hoshina, a senior naval official, attended the conference and prepared a detailed account. With Prime Minister Suzuki presiding, each of the ministers had a chance to state their views directly to Hirohito. While Army Minister Anami tacitly threatened a coup (“civil war”), the emperor accepted the majority view that the reply to the Potsdam declaration should include only one condition not the four urged by “Big Six.” Nevertheless, the condition that Hirohito accepted was not the one that foreign minister Togo had brought to the conference. What was at stake was the definition of the  kokutai  (national policy). Togo’s proposal would have been generally consistent with a constitutional monarchy because it defined the  kokutai  narrowly as the emperor and the imperial household. What Hirohito accepted, however, was a proposal by the extreme nationalist Kiichiro Hiranuma which drew upon prevailing understandings of the  kokutai : the “mythical notion” that the emperor was a living god. “This was the affirmation of the emperor’s theocratic powers, unencumbered by any law, based on Shinto gods in antiquity, and totally incompatible with a constitutional monarchy.” Thus, the Japanese response to the Potsdam declaration opposed “any demand which prejudices the prerogatives of his Majesty as a sovereign ruler.” This proved to be unacceptable to the Truman administration. [63]

Document 76 :“Magic’ – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 508, August 10, 1945

More intercepted messages on the bombing of Hiroshima.

Documents 77A-B: The First Japanese Offer Intercepted

77A . “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1233 – August 10, 1945, Top Secret Ultra

77B . Translation of intercepted Japanese messages, circa 10 August 10, 1945, Top Secret Ultra

The first Japanese surrender offer was intercepted shortly before Tokyo broadcast it. This issue of the diplomatic summary also includes Togo’s account of his notification of the Soviet declaration of war, reports of Soviet military operations in the Far East, and intercepts of French diplomatic traffic. A full translation of the surrender offer was circulated separately. The translations differ but they convey the sticking point that prevented U.S. acceptance: Tokyo’s condition that the allies not make any “demand which prejudices the prerogatives of His Majesty as a sovereign ruler.”

Document 78 : Diary Entry, Friday, August 10, 1945, Henry Wallace Diary

Source: Papers of Henry A. Wallace, Special Collections Department, University of Iowa Libraries, Iowa City, Iowa (copy courtesy of Special Collections Department)

Note: The second page of the diary entry includes a newspaper clipping of the Associated Press’s transmission of the Byrnes note. Unfortunately, AP would not authorize the Archive to reproduce this item without payment. Therefore, we are publishing an excised version of the entry, with a link to the  Byrnes note .

Secretary of Commerce (and former Vice President) Henry Wallace provided a detailed report on the cabinet meeting where Truman and his advisers discussed the Japanese surrender offer, Russian moves into Manchuria, and public opinion on “hard” surrender terms. With Japan close to capitulation, Truman asserted presidential control and ordered a halt to atomic bombings. Barton J. Bernstein has suggested that Truman’s comment about “all those kids” showed his belated recognition that the bomb caused mass casualties and that the target was not purely a military one. [64]

Document 79 : Entries for 10-11 August, Robert P. Meiklejohn Diary

In these entries, Meiklejohn discussed how he and others in the Moscow Embassy learned about the bombing of Nagasaki from the “OWI Bulletin.” Entries for 10 and 11 August cover discussion at the Embassy about the radio broadcast announcing that Japan would surrender as long the Emperor’s status was not affected. Harriman opined that “surrender is in the bag” because of the Potsdam Declaration’s provision that the Japanese could “choose their own form of government, which would probably include the Emperor.” Further, “the only alternative to the Emperor is Communism,” implying that an official role for the Emperor was necessary to preserve social stability and prevent social revolution.

Document 80 : Stimson Diary Entries, Friday and Saturday, August 10 and 11, 1945

Stimson’s account of the events of 10 August focused on the debate over the reply to the Japanese note, especially the question of the Emperor’s status.  The U.S. reply , drafted during the course of the day, did not explicitly reject the note but suggested that any notion about the “prerogatives” of the Emperor would be superceded by the concept that all Japanese would be “Subject to the Supreme Commander of the Allied Powers.” The language was ambiguous enough to enable Japanese readers, upon Hirohito’s urging, to believe that they could decide for themselves the Emperor’s future role. Stimson accepted the language believing that a speedy reply to the Japanese would allow the United States to “get the homeland into our hands before the Russians could put in any substantial claim to occupy and help rule it.” If the note had included specific provision for a constitutional monarchy, Hasegawa argues, it would have “taken the wind out of the sails” of the military faction and Japan might have surrendered several days earlier, on August 11 or 12 instead of August 14. [65]

Document 81 : Entries from Walter Brown Diary, 10-11 August 1945

Source:  Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter Brown Papers, box 68, folder 13, “Transcript/Draft B

Brown recounted Byrnes’ debriefing of the 10 August White House meeting on the Japanese peace offer, an account which differed somewhat from that in the Stimson diary .  According to what Byrnes told Brown, Truman, Stimson, and Leahy favored accepting the Japanese note, but Byrnes objected that the United States should “go [no] further than we were willing to go at Potsdam.” Stimson’s account of the meeting noted Byrnes’ concerns (“troubled and anxious”) about the Japanese note and implied that he (Stimson) favored accepting it, but did not picture the debate as starkly as Browns's did.

Document 82 : General L. R. Groves to Chief of Staff George C. Marshall,  August 10, 1945, Top Secret, with a hand-written note by General Marshall

Source: George C. Marshall Papers, George C. Marshall Library, Lexington, VA (copy courtesy of Barton J. Bernstein)

Groves informed General Marshall that he was making plans for the use of a third atomic weapon sometime after 17 August, depending on the weather. With Truman having ordered a halt to the atomic bombings [See document 78], Marshall wrote on Grove's memo that the bomb was “not to be released over Japan without express authority from the President.”

Document 83 : Memorandum of Conversation, “Japanese Surrender Negotiations,” August 10, 1945, Top Secret

Source: Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 10-12, 1945

Japan’s prospective surrender was the subject of detailed discussion between Harriman, British Ambassador Kerr, and Soviet Foreign Minister Molotov during the evening of August 10 (with a follow-up meeting occurring at 2 a.m.). In the course of the conversation, Harriman received a message from Washington that included the proposed U.S. reply and a request for Soviet support of the reply. After considerable pressure from Harriman, the Soviets signed off on the reply but not before tensions surfaced over the control of Japan--whether Moscow would have a Supreme Commander there as well. This marked the beginning of a U.S.-Soviet “tug of war” over occupation arrangements for Japan. [66]

Document 84 : Admiral Tagaki Diary Entry for 12 August [1945] Source: Takashi Itoh, ed.,  Sokichi Takagi: Nikki to Joho  [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 926-927 [Translation by Hikaru Tajima]

As various factions in the government maneuvered on how to respond to the Byrnes note, Navy Minister Yonai and Admiral Tagaki discussed the latest developments. Yonai was upset that Chief of Staff Yoshijiro Umezu and naval chief Suemu Toyada had sent the emperor a memorandum arguing that acceptance of the Brynes note would “desecrate the emperor’s dignity” and turn Japan into virtually a “slave nation.” The emperor chided Umezu and Toyoda for drawing hasty conclusions; in this he had the support of Yonai, who also dressed them down. As Yonai explained to Tagaki, he had also confronted naval vice Chief Takijiro Onishi to make sure that he obeyed any decision by the Emperor. Yonai made sure that Takagi understood his reasons for bringing the war to an end and why he believed that the atomic bomb and the Soviet declaration of war had made it easier for Japan to surrender. [67]

Document 85 : Memorandum from Major General Clayton Bissell, Assistant Chief of Staff, G-2, for the Chief of Staff, “Estimate of Japanese Situation for Next 30 Days,” August 12, 1945, Top Secret

Source: National Archives, RG 165, Army Operations OPD, Executive Files 1940-1945, box 12, Exec #2

Not altogether certain that surrender was imminent, Army intelligence did not rule out the possibility that Tokyo would try to “drag out the negotiations” or reject the Byrnes proposal and continue fighting. If the Japanese decided to keep fighting, G-2 opined that “Atomic bombs will not have a decisive effect in the next 30 days.” Richard Frank has pointed out that this and other documents indicate that high level military figures remained unsure as to how close Japan really was to surrender.

Document 86 : The Cabinet Meeting over the Reply to the Four Powers (August 13)

Source:  Gaimusho [Ministry of Foreign Affairs], ed., Shusen Shiroku [Historical Record of the End of the War] (Tokyo: Hokuyosha, 1977-1978), vol. 5, 27-35 [Translated by Toshihiro Higuchi]

The Byrnes Note did not break the stalemate at the cabinet level. An account of the cabinet debates on August 13 prepared by Information Minister Toshiro Shimamura showed the same divisions as before; Anami and a few other ministers continued to argue that the Allies threatened the  kokutai  and that setting the four conditions (no occupation, etc.) did not mean that the war would continue. Nevertheless, Anami argued, “We are still left with some power to fight.” Suzuki, who was working quietly with the peace party, declared that the Allied terms were acceptable because they gave a “dim hope in the dark” of preserving the emperor. At the end of the meeting, he announced that he would report to Hirohito and ask him to make another “Sacred Judgment”. Meanwhile, junior Army officers plotted a coup to thwart the plans for surrender. [68]

Document 87 : Telephone conversation transcript, General Hull and Colonel Seaman [sic] – 1325 – 13 Aug 45, Top Secret

Source: George C. Marshall Library, Lexington, VA, George C. Marshall Papers (copy courtesy of Barton J. Bernstein)

While Truman had rescinded the order to drop nuclear bombs, the war was not yet over and uncertainty about Japan’s next step motivated war planner General John E. Hull (assistant chief of staff for the War Department’s Operations Division), and one of Groves’ associates, Colonel L. E. Seeman, to continue thinking about further nuclear use and its relationship to a possible invasion of Japan. As Hull explained, “should we not concentrate on targets that will be of greatest assistance to an invasion rather than industry, morale, psychology, etc.” “Nearer the tactical use”, Seaman agreed and they discussed the tactics that could be used for beach landings. In 1991 articles, Barton Bernstein and Marc Gallicchio used this and other evidence to develop the argument that concepts of tactical nuclear weapons use first came to light at the close of World War II. [69]

Document 88 : “Magic” – Diplomatic Summary, War Department, Office of Assistant Chief of Staff, G-2, No. 1236 – August 13, 1945, Top Secret Ultra

The dropping of two atomic bombs, the tremendous destruction caused by U.S. bombing, and the Soviet declaration of war notwithstanding, important elements of the Japanese Army were unwilling to yield, as was evident from intercepted messages dated 12 and 13 August. Willingness to accept even the “destruction of the Army and Navy” rather than surrender inspired the military coup that unfolded and failed during the night of 14 August.

Document 89 : “The Second  Sacred Judgment”, August 14, 1945

Source :   Hiroshi [Kaian) Shimomura, S husenki [Account of the End of the War]  (Tokyo, Kamakura Bunko, [1948], 148-152 [Translated by Toshihiro Higuchi]

Frightened by the rapid movement of Soviet forces into Manchuria and worried that the army might launch a coup, the peace party set in motion a plan to persuade Hirohito to meet with the cabinet and the “Big Six” to resolve the stalemate over the response to the Allies. Japan was already a day late in responding to the Byrnes Note and Hirohito agreed to move quickly. At 10:50 a.m., he met with the leadership at the bomb shelter in his palace. This account, prepared by Director of Information Shimomura, conveys the drama of the occasion (as well as his interest in shifting the blame for the debacle to the Army). After Suzuki gave the war party--Umeda, Toyoda, and Anami--an opportunity to present their arguments against accepting the Byrnes Note, he asked the emperor to speak. 

  Hirohito asked the leadership to accept the Note, which he believed was “well intentioned” on the matter of the “national polity” (by leaving open a possible role for the Emperor).  Arguing that continuing the war would reduce the nation “to ashes,” his words about “bearing the unbearable” and sadness over wartime losses and suffering prefigured the language that Hirohito would use in his public announcement the next day. According to Bix, “Hirohito's language helped to transform him from a war to a peace leader, from a cold, aloof monarch to a human being who cared for his people” but “what chiefly motivated him … was his desire to save a politically empowered throne with himself on it.” [70]

Hirohito said that he would make a recording of the surrender announcement so that the nation could hear it. That evening army officers tried to seize the palace and find Hirohito’s recording, but the coup failed. Early the next day, General Anami committed suicide. On the morning of August 15, Hirohito broadcast the message to the nation (although he never used the word “surrender”). A few weeks later, on September 2, 1945 Japanese representatives signed surrender documents on the USS  Missouri , in Tokyo harbor. [71]

Document 90 : “Magic” – Far East Summary, War Department, Office of Assistant Chief of Staff, G-2, no. 515, August 18, 1945

This summary includes an intercepted account of the destruction of Nagasaki.

Document 91 :Washington Embassy Telegram 5599 to Foreign Office, 14 August 1945, Top Secret [72]

Source: The British National Archives, Records of the Foreign and Commonwealth Office,  FO 800/461

With the Japanese surrender announcement not yet in, President Truman believed that another atomic bombing might become necessary. After a White House meeting on 14 August, British Minister John Balfour reported that Truman had “remarked sadly that he now had no alternative but to order an atomic bomb to be dropped on Tokyo.” This was likely emotional thinking spurred by anxiety and uncertainty. Truman was apparently not considering the fact that Tokyo was already devastated by fire bombing and that an atomic bombing would have killed the Emperor, which would have greatly complicated the process of surrender. Moreover, he may not have known that the third bomb was still in the United States and would not be available for use for nearly another week. [73]  As it turned out, a few hours later, at 4:05 p.m., the White House received the Japanese surrender announcement.

XI. Confronting the Problem of Radiation Poisoning

Document 92 : P.L. Henshaw and R.R. Coveyou to H.J. Curtis and K. Z. Morgan, “Death from Radiation Burns,” 24 August 1945, Confidential

Source: Department of Energy Open-Net

Two scientists at Oak Ridge’s Health Division, Henshaw and Coveyou, saw a United Press report in the Knoxville  News Sentinel  about radiation sickness caused by the bombings. Victims who looked healthy weakened, “for unknown reasons” and many died. Lacking direct knowledge of conditions in Hiroshima and Nagasaki, Henshaw and Coveyou had their own data on the biological effects of radiation and could make educated guesses. After reviewing the impact of various atomic bomb effects--blast, heat, flash radiation (prompt effects from gamma waves), and radiation from radioactive substances--they concluded that “it seems highly plausible that a great many persons were subjected to lethal and sub-lethal dosages of radiation in areas where direct blast effects were possibly non-lethal.” It was “probable,” therefore, that radiation “would produce increments to the death rate and “even more probable” that a “great number of cases of sub-lethal exposures to radiation have been suffered.” [74]

Document 93 : Memorandum of Telephone Conversation Between General Groves and Lt. Col. Rea, Oak Ridge Hospital, 9:00 a.m., August 28, 1945, Top Secret

Source: RG 77, MED Records, Top Secret Documents, File no. 5b

Despite the reports pouring in from Japan about radiation sickness among the victims of Hiroshima and Nagasaki, General Groves and Dr. Charles Rea, a surgeon who was head of the base hospital at Oak Ridge (and had no specialized knowledge about the biological effects of radiation) dismissed the reports as “propaganda”. Unaware of the findings of Health Division scientists, Groves and Rhea saw the injuries as nothing more than “good thermal burns.” [75]

Documents 94A-B: General Farrell Surveys the Destruction

94A . Cable CAX 51813 from  USS Teton  to Commander in Chief Army Forces Pacific Administration, From Farrell to Groves, September 10, 1945, Secret

94B . Cable CAX 51948 from Commander in Chief Army Forces Pacific Advance Yokohoma Japan to Commander in Chief Army Forces Pacific Administration, September 14, 1945, Secret

Source: RG 77, Tinian Files, April-December 1945, box 17, Envelope B

A month after the attacks Groves’ deputy, General Farrell, traveled to Japan to see for himself the destruction of Hiroshima and Nagasaki. His vivid account shows that senior military officials in the Manhattan Project were no longer dismissive of reports of radiation poisoning. As Farrell observed in his discussion of Hiroshima, “Summaries of Japanese reports previously sent are essentially correct, as to clinical effects from single gamma radiation dose.” Such findings dismayed Groves, who worried that the bomb would fall into a taboo category like chemical weapons, with all the fear and horror surrounding them. Thus, Groves and others would try to suppress findings about radioactive effects, although that was a losing proposition. [76]

XII. Eisenhower and McCloy’s Views on the Bombings and Atomic Weapons

Document 95 : Entry for 4 October 1945, Robert P. Meiklejohn Diary

In this entry written several months later, Meiklejohn shed light on what much later became an element of the controversy over the Hiroshima-Nagasaki bombings: whether any high level civilian or military officials objected to nuclear use. Meiklejohn recounted Harriman’s visit in early October 1945 to the Frankfurt-area residence of General Dwight Eisenhower, who was finishing up his service as Commanding General, U.S. Army, European Theater. It was Meiklejohn’s birthday and during the dinner party, Eisenhower and McCloy had an interesting discussion of atomic weapons, which included comments alluding to scientists’ statements about what appears to be the H-bomb project (a 20 megaton weapon), recollection of the early fear that an atomic detonation could burn up the atmosphere, and the Navy’s reluctance to use its battleships to test atomic weapons. At the beginning of the discussion, Eisenhower made a significant statement: he “mentioned how he had hoped that the war might have ended without our having to use the atomic bomb.” The general implication was that prior to Hiroshima-Nagasaki, he had wanted to avoid using the bomb.

Some may associate this statement with one that Eisenhower later recalled making to Stimson. In his 1948 memoirs (further amplified in his 1963 memoirs), Eisenhower claimed that he had “expressed the hope [to Stimson] that we would never have to use such a thing against an enemy because I disliked seeing the United States take the lead in introducing into war something as horrible and destructive as this new weapon was described to be.” That language may reflect the underlying thinking behind Eisenhower’s statement during the dinner party, but whether Eisenhower used such language when speaking with Stimson has been a matter of controversy. In later years, those who knew both thought it unlikely that the general would have expressed misgivings about using the bomb to a civilian superior. Eisenhower’s son John cast doubts about the memoir statements, although he attested that when the general first learned about the bomb he was downcast.

Stimson’s diary mentions meetings with Eisenhower twice in the weeks before Hiroshima, but without any mention of a dissenting Eisenhower statement (and Stimson’s diaries are quite detailed on atomic matters). The entry from Meiklejohn’s diary does not prove or disprove Eisenhower’s recollection, but it does confirm that he had doubts which he expressed only a few months after the bombings. Whether Eisenhower expressed such reservations prior to Hiroshima will remain a matter of controversy. [77]

Document 96:  President Harry S. Truman, Handwritten Remarks for Gridiron Dinner, circa 15 December 1945 [78]

Source: Harry S. Truman Library,  President's Secretary's Files,  Speech Files, 1945-1953,  copy on U.S. National Archives Web Site

On 15 December, President Truman spoke about the atomic bombings in his speech at the annual dinner of the Gridiron Club, organized by bureau chiefs and other leading figures of print media organizations. Besides Truman, guests included New York Governor Thomas Dewey (Republican presidential candidate in 1944 and 1948), foreign ambassadors, members of the cabinet and the Supreme Court, the military high command, and various senators and representatives. The U.S. Marine Band provided music for the dinner and for the variety show that was performed by members of the press.  [79]

In accordance with the dinner’s rules that “reporters are never present,” Truman’s remarks were off-the record. The president, however, wrote in long-hand a text that that might approximate what he said that evening. Pages 12 through 15 of those notes refer to the atomic bombing of Japan:

“You know the most terrible decision a man ever had to make was made by me at Potsdam. It had nothing to do with Russia or Britain or Germany. It was a decision to loose the most terrible of all destructive forces for the wholesale slaughter of human beings. The Secretary of War, Mr. Stimson, and I weighed that decision most prayerfully. But the President had to decide. It occurred to me that a quarter of a million of the flower of our young manhood was worth a couple of Japanese cities, and I still think that they were and are. But I couldn’t help but think of the necessity of blotting out women and children and non-combatants. We gave them fair warning and asked them to quit. We picked a couple of cities where war work was the principle industry, and dropped bombs. Russia hurried in and the war ended.”

Truman characterized the Potsdam Declaration as a “fair warning,” but it was an ultimatum. Plainly he was troubled by the devastation and suffering caused by the bombings, but he found it justifiable because it saved the lives of U.S. troops. His estimate of 250,000 U.S. soldiers spared far exceeded that made by General Marshall in June 1945, which was in the range of 31,000 (comparable to the Battle of Luzon) [See Document 26]. By citing an inflated casualty figure, the president was giving a trial run for the rationale that would become central to official and semi-official discourse about the bombings during the decades ahead. [80]  

Despite Truman’s claim that he made “the most terrible” decision at Potsdam, he assigned himself more responsibility than the historical record supports. On the basic decision, he had simply concurred with the judgments of Stimson, Groves, and others that the bomb would be used as soon as it was available for military use. As for targeting, however, he had a more significant role. At Potsdam, Stimson raised his objections to targeting Japan’s cultural capital, Kyoto, and Truman supported the secretary’s efforts to drop that city from the target list [See Documents 47 and 48].  [81]

Where he had taken significant responsibility was by making a decision to stop the atomic bombings just before the Japanese surrender, thereby asserting presidential control over nuclear weapons

The editor thanks Barton J. Bernstein, J. Samuel Walker, Gar Alperovitz, David Holloway, and Alex Wellerstein for their advice and assistance, and Tsuyoshi Hasegawa for kindly providing copies of some of the Japanese sources that were translated for this compilation. Hasegawa’s book,  Racing the Enemy: Stalin, Truman, and the Surrender of Japan  (Cambridge, Harvard University Press, 2005), includes invaluable information on Japanese sources. David Clark, an archivist at the Harry S. Truman Library, and James Cross, Manuscripts Archivist at Clemson University Library’s Special Collections, kindly provided material from their collections. The editor also thanks Kyle Hammond and Gregory Graves for research assistance and Toshihiro Higuchi and Hikaru Tajima (who then were graduate students in history at Georgetown University and the University of Tokyo respectively), for translating documents and answering questions on the Japanese sources. The editor thanks Anna Melyakova (National Security Archive) for translating Russian language material.

Read the documents

I. background on the u.s. atomic project   documents 1a-c: report of the uranium committee.

Document 1A

National Archives, Records of the Office of Scientific Research and Development, Record Group 227 (hereinafter RG 227), Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section A (1940-1941)."

Document 1B

See description of document 1A.

Document 1C

Document 2A

RG 227, Bush-Conant papers microfilm collection, Roll 1, Target 2, Folder 1, "S-1 Historical File, Section II (1941-1942)

Document 2B

Bush-Conant papers, S-1 Historical File, Reports to and Conferences with the President (1942-1944)

See description of document 2A.

National Archives, Record Group 77, Records of the Army Corps of Engineers (hereinafter RG 77), Manhattan Engineering District (MED), Minutes of the Military Policy Meeting (5 May 1943), Correspondence (“Top Secret”) of the Manhattan Engineer District, 1942-1946, microfilm publication M1109 (Washington, D.C.: National Archives and Records Administration, 1980), Roll 3, Target 6, Folder 23, “Military Policy Committee, Minutes of Meetings”

Before the Manhattan Project had produced any weapons, senior U.S. government officials had Japanese targets in mind. Besides discussing programmatic matters (e.g., status of gaseous diffusion plants, heavy water production for reactors, and staffing at Las Alamos), the participants agreed that the first use could be Japanese naval forces concentrated at Truk Harbor, an atoll in the Caroline Islands. If there was a misfire the weapon would be difficult for the Japanese to recover, which would not be the case if Tokyo was targeted. Targeting Germany was rejected because the Germans were considered more likely to “secure knowledge” from a defective weapon than the Japanese. That is, the United States could possibly be in danger if the Nazis acquired more knowledge about how to build a bomb. [9]

RG 77, Correspondence ("Top Secret") of the Manhattan Engineer District, 1942-1946, file 25M

This memorandum from General Groves to General Marshall captured how far the Manhattan Project had come in less than two years since Bush’s December 1942 report to President Roosevelt. Groves did not mention this but around the time he wrote this the Manhattan Project had working at its far-flung installations over 125,000 people ; taking into account high labor turnover some 485,000 people worked on the project (1 out of every 250 people in the country at that time). What these people were laboring to construct, directly or indirectly, were two types of weapons—a gun-type weapon using U-235 and an implosion weapon using plutonium (although the possibility of U-235 was also under consideration). As the scientists had learned, a gun-type weapon based on plutonium was “impossible” because that element had an “unexpected property”: spontaneous neutron emissions would cause the weapon to “fizzle.” [10] For both the gun-type and the implosion weapons, a production schedule had been established and both would be available during 1945. The discussion of weapons effects centered on blast damage models; radiation and other effects were overlooked.

RG 77, Harrison-Bundy Files (H-B Files), folder 69 (copy from microfilm)

Documents 6A-D: President Truman Learns the Secret

Document 6A

G 77, Commanding General’s file no. 24, tab D

Soon after he was sworn in as president following President Roosevelt’s death, Harry Truman learned about the top secret Manhattan Project from briefings by  Secretary of War Stimson and Manhattan Project chief General Groves (who went through the “back door” to escape the watchful press). Stimson, who later wrote up the meeting in his diary, also prepared a discussion paper, which raised broader policy issues associated with the imminent possession of “the most terrible weapon ever known in human history.”

In a background report prepared for the meeting, Groves provided a detailed overview of the bomb project from the raw materials to processing nuclear fuel to assembling the weapons to plans for using them, which were starting to crystallize. With respect to the point about assembling the weapons, Groves and Stimson informed Truman that the first gun-type weapon “should be ready about 1 August 1945” while an implosion weapon would also be available that month. “The target is and was always expected to be Japan.”  

These documents have important implications for the perennial debate over whether Truman “inherited assumptions” from the Roosevelt administration that the bomb would be used when available or that he made  the  decision to do so.  Alperovitz and Sherwin have argued that Truman made “a real decision” to use the bomb on Japan by choosing “between various forms of diplomacy and warfare.” In contrast, Bernstein found that Truman “never questioned [the] assumption” that the bomb would and should be used. Norris also noted that “Truman’s ”decision” amounted to a decision not to override previous plans to use the bomb.” [12]

Document 6B

Henry Stimson Diary, Sterling Library, Yale University (microfilm at Library of Congress)

See description of document 6A.

Document 6C

Record Group 200, Papers of General Leslie R. Groves, Correspondence 1941-1970, box 3, “F”

Document 6D

RG 77, MED Records, Top Secret Documents, File no. 5g

The force of B-29 nuclear delivery vehicles that was being readied for first nuclear use—the Army Air Force’s 509 th Composite Group—required an operational base in the Western Pacific. In late February 1945, months before atomic bombs were ready for use, the high command selected Tinian, an island in the Northern Marianas Islands, for that base.

Library of Congress, Curtis LeMay Papers, Box B-36

As part of the war with Japan, the Army Air Force waged a campaign to destroy major industrial centers with incendiary bombs. This document is General Curtis LeMay’s report on the firebombing of Tokyo--“the most destructive air raid in history”--which burned down over 16 square miles of the city, killed up to 100,000 civilians (the official figure was 83,793), injured more than 40,000, and made over 1 million homeless. [13] According to the “Foreword,” the purpose of the raid, which dropped 1,665 tons of incendiary bombs, was to destroy industrial and strategic targets “ not to bomb indiscriminately civilian populations.” Air Force planners, however, did not distinguish civilian workers from the industrial and strategic structures that they were trying to destroy.

RG 77, MED Records, Top Secret Documents, File no. 5d (copy from microfilm)

On 27 April, military officers and nuclear scientists met to discuss bombing techniques, criteria for target selection, and overall mission requirements. The discussion of “available targets” included Hiroshima, the “largest untouched target not on the 21 st Bomber Command priority list.” But other targets were under consideration, including Yawata (northern Kyushu), Yokohama, and Tokyo (even though it was practically “rubble.”) The problem was that the Air Force had a policy of “laying waste” to Japan’s cities which created tension with the objective of reserving some urban targets for nuclear destruction. [16]

Document 10

RG 77, MED Records, Top Secret Documents, File no. 5g (copy from microfilm)

As director of Los Alamos Laboratory, Oppenheimer’s priority was producing a deliverable bomb, but not so much the effects of the weapon on the people at the target. In keeping with General Groves’ emphasis on compartmentalization, the Manhattan Project experts on the effects of radiation on human biology were at the MetLab and other offices and had no interaction with the production and targeting units. In this short memorandum to Groves’ deputy, General Farrell, Oppenheimer explained the need for precautions because of the radiological dangers of a nuclear detonation. The initial radiation from the detonation would be fatal within a radius of about 6/10ths of a mile and “injurious” within a radius of a mile. The point was to keep the bombing mission crew safe; concern about radiation effects had no impact on targeting decisions. [17]

Document 11

Scientists and officers held further discussion of bombing mission requirements, including height of detonation, weather, radiation effects (Oppenheimer’s memo), plans for possible mission abort, and the various aspects of target selection, including priority cities (“a large urban area of more than three miles diameter”) and psychological dimension. As for target cities, the committee agreed that the following should be exempt from Army Air Force bombing so they would be available for nuclear targeting: Kyoto, Hiroshima, Yokohama, and Kokura Arsenal. Japan’s cultural capital, Kyoto, would not stay on the list. Pressure from Secretary of War Stimson had already taken Kyoto off the list of targets for incendiary bombings and he would successfully object to the atomic bombing of that city. [18]

Document 12

Document 13

Joseph E. Davies Papers, Library of Congress, box 17, 21 May 1945

Document 14

Harrison-Bundy Files relating to the Development of the Atomic Bomb, 1942-1946, microfilm publication M1108 (Washington, D.C.: National Archives and Records Administration, 1980), File 77: "Interim Committee - International Control."

In what Stimson called the “letter of an honest man,” Oswald C. Brewster sent President Truman a profound analysis of the danger and unfeasibility of a U.S. atomic monopoly. [21] An engineer for the Kellex Corporation, which was involved in the gas diffusion project to enrich uranium, Brewster recognized that the objective was fissile material for a weapon. That goal, he feared, raised terrifying prospects with implications for the “inevitable destruction of our present day civilization.” Once the U.S. had used the bomb in combat other great powers would not tolerate a monopoly by any nation and the sole possessor would be “be the most hated and feared nation on earth.” Even the U.S.’s closest allies would want the bomb because “how could they know where our friendship might be five, ten, or twenty years hence.” Nuclear proliferation and arms races would be certain unless the U.S. worked toward international supervision and inspection of nuclear plants.

Document 15

Document 16

At the end of May General Groves forwarded to Army Chief of Staff Marshall a “Plan of Operations” for the atomic bombings. While that plan has not surfaced, apparently its major features were incorporated in this 29 May 1945 message on the “special functions” of the 509th Composite Group sent from Chief of Staff General Lauris Norstad to General Curtis LeMay, chief of the XXI Bomber Command, headquartered in the Marianas Islands. [21A] The Norstad message reviewed the complex requirements for preparing B-29s and their crew for delivering nuclear weapons.  He detailed the mission of the specially modified B-29s that comprised the  509th Composite Group, the “tactical factors” that applied,  training and rehearsal issues, and the functions of “special personnel” and the Operational Studies Group.  The targets listed—Hiroshima, Kyoto, and Niigato—were those that had been discussed at the Target Committee meeting on 28 May, but Kyoto would be dropped when Secretary Stimson objected (although that would remain a contested matter) and Kokura would eventually be substituted.   As part of the Composite Group’s training to drop “special bombs,” it would practice with facsimiles—the conventionally-armed “Pumpkins.” The 509th Composite Group’s cover story for its secret mission was the preparation for the use of “Pumpkins” in battle.

Document 17

Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 12, S-1

Tacitly dissenting from the Targeting Committee’s recommendations, Army Chief of Staff George Marshall argued for initial nuclear use against a clear-cut military target such as a “large naval installation.” If that did not work, manufacturing areas could be targeted, but only after warning their inhabitants. Marshall noted the “opprobrium which might follow from an ill considered employment of such force.” This document has played a role in arguments developed by Barton J. Bernstein that figures such as Marshall and Stimson were “caught between an older morality that opposed the intentional killing of non-combatants and a newer one that stressed virtually total war.” [22]

Document 18

RG 77, MED Records, H-B files, folder no. 100 (copy from microfilm)

With Secretary of War Stimson presiding, members of the committee heard reports on a variety of Manhattan Project issues, including the stages of development of the atomic project,  problems of secrecy, the possibility of informing the Soviet Union, cooperation with “like-minded” powers, the military impact of the bomb on Japan, and the problem of “undesirable scientists.”  In his comments on a detonation over Japanese targets, Oppenheimer mentioned that the “neutron effect would be dangerous to life for a radius of at least two-thirds of a mile,” but did not mention that the radiation could cause prolonged sickness.

Interested in producing the “greatest psychological effect,” the Committee members agreed that the “most desirable target would be a vital war plant employing a large number of workers and closely surrounded by workers’ houses.”  Bernstein argues that this target choice represented an uneasy endorsement of “terror bombing”-the target was not exclusively military or civilian; nevertheless, worker’s housing would include non-combatant men, women, and children. [23] It is possible that Truman was informed of such discussions and their conclusions, although he clung to a belief that the prospective targets were strictly military.

Document 19

Record Group 165, Records of the War Department General and Special Staffs, American-British-Canadian Top Secret Correspondence, Box 504, “ABC 387 Japan (15 Feb. 45)

George A. Lincoln, chief of the Strategy and Policy Group at U.S. Army’s Operations Department, commented on a memorandum by former President Herbert Hoover that Stimson had passed on for analysis. Hoover proposed a compromise solution with Japan that would allow Tokyo to retain part of its empire in East Asia (including Korea and Japan) as a way to head off Soviet influence in the region. While Lincoln believed that the proposed peace teams were militarily acceptable he doubted that they were workable or that they could check Soviet “expansion” which he saw as an inescapable result of World War II. As to how the war with Japan would end, he saw it as “unpredictable,” but speculated that “it will take Russian entry into the war, combined with a landing, or imminent threat of a landing, on Japan proper by us, to convince them of the hopelessness of their situation.” Lincoln derided Hoover’s casualty estimate of 500,000. J. Samuel Walker has cited this document to make the point that “contrary to revisionist assertions, American policymakers in the summer of 1945 were far from certain that the Soviet invasion of Manchuria would be enough in itself to force a Japanese surrender.” [24]

Document 20

Document 21

Henry Stimson Papers, Sterling Library, Yale University (microfilm at Library of Congress)

Stimson and Truman began this meeting by discussing how they should handle a conflict with French President DeGaulle over the movement by French forces into Italian territory. (Truman finally cut off military aid to France to compel the French to pull back). [25] As evident from the discussion, Stimson strongly disliked de Gaulle whom he regarded as “psychopathic.” The conversation soon turned to the atomic bomb, with some discussion about plans to inform the Soviets but only after a successful test. Both agreed that the possibility of a nuclear “partnership” with Moscow would depend on “quid pro quos”: “the settlement of the Polish, Rumanian, Yugoslavian, and Manchurian problems.”

At the end, Stimson shared his doubts about targeting cities and killing civilians through area bombing because of its impact on the U.S.’s reputation as well as on the problem of finding targets for the atomic bomb. Barton Bernstein has also pointed to this as additional evidence of the influence on Stimson of an “an older morality.” While concerned about the U.S.’s reputation, Stimson did not want the Air Force to bomb Japanese cities so thoroughly that the “new weapon would not have a fair background to show its strength,” a comment that made Truman laugh. The discussion of “area bombing” may have reminded him that Japanese civilians remained at risk from U.S. bombing operations.

Document 22

RG 77, MED Records, H-B files, folder no. 76 (copy from microfilm)

Physicists Leo Szilard and James Franck, a Nobel Prize winner, were on the staff of the “Metallurgical Laboratory” at the University of Chicago, a cover for the Manhattan Project program to produce fuel for the bomb. The outspoken Szilard was not involved in operational work on the bomb and General Groves kept him under surveillance but Met Lab director Arthur Compton found Szilard useful to have around. Concerned with the long-run implications of the bomb, Franck chaired a committee, in which Szilard and Eugene Rabinowitch were major contributors, that produced a report rejecting a surprise attack on Japan and recommended instead a demonstration of the bomb on the “desert or a barren island.” Arguing that a nuclear arms race “will be on in earnest not later than the morning after our first demonstration of the existence of nuclear weapons,” the committee saw international control as the alternative. That possibility would be difficult if the United States made first military use of the weapon. Compton raised doubts about the recommendations but urged Stimson to study the report. Martin Sherwin has argued that the Franck committee shared an important assumption with Truman et al.--that an “atomic attack against Japan would `shock’ the Russians”--but drew entirely different conclusions about the import of such a shock. [26]

Document 23

Record Group 107, Office of the Secretary of War, Formerly Top Secret Correspondence of Secretary of War Stimson (“Safe File”), July 1940-September 1945, box 8, Japan (After December 7/41)

Document 24

Document 25

Document 26

Record Group 218, Records of the Joint Chiefs of Staff, Central Decimal Files, 1942-1945, box 198 334 JCS (2-2-45) Mtg 186th-194th

The record of this meeting has figured in the complex debate over the estimates of casualties stemming from a possible invasion of Japan. While post-war justifications for the bomb suggested that an invasion of Japan could have produced very high levels of casualties (dead, wounded, or missing), from hundreds of thousands to a million, historians have vigorously debated the extent to which the estimates were inflated. [29]

Document 27

Document 28

RG 77, MED, H-B files, folder no. 77 (copy from microfilm)

Document 29

Document 30

RG 107, Office of Assistant Secretary of War Formerly Classified Correspondence of John J. McCloy, 1941-1945, box 38, ASW 387 Japan

Document 31

Document 32

Document 33

Naval Aide to the President Files, box 4, Berlin Conference File, Volume XI - Miscellaneous papers: Japan, Harry S. Truman Presidential Library

On 2 July Stimson presented to President Truman a proposal that he had worked up with colleagues in the War Department, including McCloy, Marshall, and Grew. The proposal has been characterized as “the most comprehensive attempt by any American policymaker to leverage diplomacy” in order to shorten the Pacific War. Stimson had in mind a “carefully timed warning” delivered before the invasion of Japan. Some of the key elements of Stimson’s argument were his assumption that “Japan is susceptible to reason” and that Japanese might be even more inclined to surrender if “we do not exclude a constitutional monarchy under her present dynasty.” The possibility of a Soviet attack would be part of the “threat.” As part of the threat message, Stimson alluded to the “inevitability and completeness of the destruction” which Japan could suffer, but he did not make it clear whether unconditional surrender terms should be clarified before using the atomic bomb. Truman read Stimson’s proposal, which he said was “powerful,” but made no commitments to the details, e.g., the position of the emperor. [32]

Document 34

Record Group 353, Records of Interdepartmental and Intradepartmental Committees, Secretary’s Staff Meetings Minutes, 1944-1947 (copy from microfilm)

Document 35

RG 218, Central Decimal Files, 1943-1945, CCS 381 (6-4-45), Sec. 2 Pt. 5

Document 36

Record Group 59, Decimal Files 1945-1949, 740.0011 PW (PE)/7-1645

Document 37

Henry L. Stimson Papers (MS 465), Sterling Library, Yale University (reel 113) (microfilm at Library of Congress)

Still interested in trying to find ways to “warn Japan into surrender,” this represents an attempt by Stimson before the Potsdam conference, to persuade Truman and Byrnes to agree to issue warnings to Japan prior to the use of the bomb. The warning would draw on the draft State-War proclamation to Japan; presumably, the one criticized by Hull (above) which included language about the emperor. Presumably the clarified warning would be issued prior to the use of the bomb; if the Japanese persisted in fighting then “the full force of our new weapons should be brought to bear” and a “heavier” warning would be issued backed by the “actual entrance of the Russians in the war.” Possibly, as Malloy has argued, Stimson was motivated by concerns about using the bomb against civilians and cities, but his latest proposal would meet resistance at Potsdam from Byrnes and other. [34]

Document 38

IV. The Japanese Search for Soviet Mediation   Documents 39A-B: Magic

Document 39A

National Security Agency Mandatory declassification review release.

Beginning in September 1940, U.S. military intelligence began to decrypt routinely, under the “Purple” code-name, the intercepted cable traffic of the Japanese Foreign Ministry. Collectively the decoded messages were known as “Magic.” How this came about is explained in an internal history of pre-war and World War II Army and Navy code-breaking activities prepared by William F. Friedman , a central figure in the development of U.S. government cryptology during the 20 th century. The National Security Agency kept the ‘Magic” diplomatic and military summaries classified for many years and did not release the entire series for 1942 through August 1945 until the early 1990s. [36]

Document 39B

Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18.

Document 40

RG 165, Army Operations OPD Executive File #17, Item 13 (copy courtesy of J. Samuel Walker)

Document 41

Record Group 457, Records of the National Security Agency/Central Security Service, “Magic” Diplomatic Summaries 1942-1945, box 18

Document 42

Document 43

Takashi Itoh, ed., Sokichi Takagi: Nikki to Joho [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 916-917 [Translation by Hikaru Tajima]

Document 44

L.D. Riabev, ed., Atomnyi Proekt SSSR (Moscow: izd MFTI, 2002), Volume 1, Part 2, 335-336

This 10 July 1945 letter from NKVD director V. N. Merkulov to Beria is an example of Soviet efforts to collect inside information on the Manhattan Project, although not all the detail was accurate. Merkulov reported that the United States had scheduled the test of a nuclear device for that same day, although the actual test took place 6 days later. According to Merkulov, two fissile materials were being produced: element-49 (plutonium), and U-235; the test device was fueled by plutonium. The Soviet source reported that the weight of the device was 3 tons (which was in the ball park) and forecast an explosive yield of 5 kilotons. That figure was based on underestimates by Manhattan Project scientists: the actual yield of the test device was 20 kilotons.

Document 45

RG 77, MED Records, Top Secret Documents, File 5e (copy from microfilm)

An elated message from Harrison to Stimson reported the success of the Trinity Test of a plutonium implosion weapon. The light from the explosion could been seen “from here [Washington, D.C.] to “high hold” [Stimson’s estate on Long Island—250 miles away]” and it was so loud that Harrison could have heard the “screams” from Washington, D.C. to “my farm” [in Upperville, VA, 50 miles away] [42]

Document 46

RG 77, MED Records, Top Secret Documents, File no. 4 (copy from microfilm)

Document 47

Barton J. Bernstein, “Truman at Potsdam: His Secret Diary,” Foreign Service Journal, July/August 1980, excerpts, used with author’s permission. [44]

Some years after Truman’s death, a hand-written diary that he kept during the Potsdam conference surfaced in his personal papers. For convenience, Barton Bernstein’s rendition is provided here but linked here are the scanned versions of Truman’s handwriting on the National Archives’ website (for 15-30 July).

Document 48

An important question that Stimson discussed with Marshall, at Truman’s request, was whether Soviet entry into the war remained necessary to secure Tokyo’s surrender. Marshall was not sure whether that was so although Stimson privately believed that the atomic bomb would provide enough to force surrender (see entry for July 23). This entry has been cited by all sides of the controversy over whether Truman was trying to keep the Soviets out of the war. [46] During the meeting on August 24, discussed above, Stimson gave his reasons for taking Kyoto off the atomic target list: destroying that city would have caused such “bitterness” that it could have become impossible “to reconcile the Japanese to us in that area rather than to the Russians.” Stimson vainly tried to preserve language in the Potsdam Declaration designed to assure the Japanese about “the continuance of their dynasty” but received Truman’s assurance that such a consideration could be conveyed later through diplomatic channels (see entry for July 24). Hasegawa argues that Truman realized that the Japanese would refuse a demand for unconditional surrender without a proviso on a constitutional monarchy and that “he needed Japan’s refusal to justify the use of the atomic bomb.” [47]

Document 49

Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 10, folder 12, Byrnes, James F.: Potsdam, Minutes, July-August 1945

The degree to which the typed-up version reflects the original is worth investigating. In any event, historians have used information from the diary to support various interpretations. For example, Bernstein cites the entries for 20 and 24 July to argue that “American leaders did not view Soviet entry as a substitute for the bomb” but that the latter “would be so powerful, and the Soviet presence in Manchuria so militarily significant, that there was no need for actual Soviet intervention in the war.” For Brown's diary entry of 3 August 9 1945 historians have developed conflicting interpretations (See discussion of document 57). [48]

Document 50

Document 51

Naval Historical Center, Operational Archives, James Forrestal Diaries

Secretary of the Navy James Forrestal was a regular recipient of “Magic” intercept reports; this substantial entry reviews the dramatic Sato-Togo exchanges covered in the 22 July “Magic” summary (although Forrestal misdated Sato’s cable as “first of July” instead of the 21 st ). In contrast to Alperovitz’s argument that Forrestal tried to modify the terms of unconditional surrender to give the Japanese an out, Frank sees Forrestal’s account of the Sato-Togo exchange as additional evidence that senior U.S. officials understood that Tokyo was not on the “cusp of surrender.” [49]

Document 52

Joseph E. Davies Papers, Library of Congress, Manuscripts Division, box 19, 29 July 1945

VII. Debates among the Japanese – Late July/Early August 1945

Document 53

In the Potsdam Declaration the governments of China, Great Britain, and the United States) demanded the “unconditional surrender of all Japanese armed forces. “The alternative is prompt and utter destruction.” The next day, in response to questions from journalists about the government’s reaction to the ultimatum, Prime Minister Suzuki apparently said that “We can only ignore [ mokusatsu ] it. We will do our utmost to complete the war to the bitter end.” That, Bix argues, represents a “missed opportunity” to end the war and spare the Japanese from continued U.S. aerial attacks. [51] Togo’s private position was more nuanced than Suzuki’s; he told Sato that “we are adopting a policy of careful study.” That Stalin had not signed the declaration (Truman and Churchill did not ask him to) led to questions about the Soviet attitude. Togo asked Sato to try to meet with Soviet Foreign Minister Molotov as soon as possible to “sound out the Russian attitude” on the declaration as well as Japan’s end-the-war initiative. Sato cabled Togo earlier that he saw no point in approaching the Soviets on ending the war until Tokyo had “concrete proposals.” “Any aid from the Soviets has now become extremely doubtful.”

Document 54

Document 55

Document 56

Document 57

Document 58

RG 457, Summaries of Intercepted Japanese Messages (“Magic” Far East Summary, March 20, 1942 – October 2, 1945), box 7, SRS 491-547

Document 59

VIII. The Execution Order   Documents 60A-D: These messages convey the process of creating and transmitting the execution order to bomb Hiroshima. Possibly not wanting to take responsibility for the first use of nuclear weapons, Army Air Force commanders sought formal authorization from Chief of Staff Marshall who was then in Potsdam

Document 60A

RG 77, MED Records, Top Secret Documents, Files no. 5b and 5e (copies from microfilm)

These messages convey the process of creating and transmitting the execution order to bomb Hiroshima.  Possibly not wanting to take responsibility for the first use of nuclear weapons, Army Air Force commanders sought formal authorization from Chief of Staff Marshall who was then in Potsdam. [55] On 22 July Marshall asked Deputy Chief of Staff Thomas Handy to prepare a draft; General Groves wrote one which went to Potsdam for Marshall’s approval. Colonel John Stone, an assistant to commanding General of the Army Air Forces Henry H. “Hap” Arnold, had just returned from Potsdam and updated his boss on the plans as they had developed. On 25 July Marshall informed Handy that Secretary of War Stimson had approved the text; that same day, Handy signed off on a directive which ordered the use of atomic weapons on Japan, with the first weapon assigned to one of four possible targets—Hiroshima, Kokura, Niigata, or Nagasaki. “Additional bombs will be delivery on the [targets] as soon as made ready by the project staff.”

Document 60B

See description of document 60A.

Document 60C

Document 60D

Document 60E

Document 61

RG 77, MED Records, Top Secret Documents, File no. 5

With more information on the Alamogordo test available, Groves provided Marshall with detail on the destructive power of atomic weapons. Barton J. Bernstein has observed that Groves’ recommendation that troops could move into the “immediate explosion area” within a half hour demonstrates the prevalent lack of top-level knowledge of the dangers of nuclear weapons effects. [56] Groves also provided the schedule for the delivery of the weapons: the components of the gun-type bomb to be used on Hiroshima had arrived on Tinian, while the parts of the second weapon to be dropped were leaving San Francisco. By the end of November over ten weapons would be available, presumably in the event the war had continued.

Document 62A

RG 77, Tinian Files, April-December 1945, box 21 (copies courtesy of Barton Bernstein)

Document 62B

See description of document 62A.

Document 62C

Document 63

RG 77, MED Records, Top Secret Documents, File no. 5b (copy from microfilm)

Document 64

Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter J. Brown Papers, box 68, folder 13, “Transcript/Draft B

Returning from the Potsdam Conference, sailing on the U.S.S. Augusta , Truman learned about the atomic bombing of Hiroshima and announced it twice, first to those in the wardroom (socializing/dining area for commissioned officers), and then to the sailors’ mess. Still unaware of radiation effects, Truman emphasized the explosive yield. Later, he met with Secretary of State Byrnes and they discussed the Manhattan Project’s secrecy and the huge expenditures. Truman, who had been chair of the Senate Special Committee to Investigate the National Defense Program, said that “only on the appeal of Secretary of War Stimson did he refrain and let the War Department continue with the experiment unmolested.”

Document 65

A. Zolotarev, ed., Sovetsko-Iaponskaia Voina 1945 Goda: Istoriia Voenno-Politicheskogo Protivoborstva Dvukh Derzhav v 30–40e Gody (Moscow: Terra, 1997 and 2000), Vol. 7 (1), 340-341.

Document 66

Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945.

Documents 67A-B: Early High-level Reactions to the Hiroshima Bombing

Document 67A

Gaimusho (Ministry of Foreign Affairs) ed. Shusen Shiroku (The Historical Records of the End of the War), annotated by Jun Eto, volume 4, 57-60 [Excerpts] [Translation by Toshihiro Higuchi]

Excerpts from the Foreign Ministry's compilation about the end of the war show how news of the bombing reached Tokyo as well as how Foreign Minister's Togo initially reacted to reports about Hiroshima. When he learned of the atomic bombing from the Domei News Agency, Togo believed that it was time to give up and advised the cabinet that the atomic attack provided the occasion for Japan to surrender on the basis of the Potsdam Declaration. Togo could not persuade the cabinet, however, and the Army wanted to delay any decisions until it had learned what had happened to Hiroshima. When the Foreign Minister met with the Emperor, Hirohito agreed with him; he declared that the top priority was an early end to the war, although it would be acceptable to seek better surrender terms--probably U.S. acceptance of a figure-head emperor--if it did not interfere with that goal. In light of those instructions, Togo and Prime Minister Suzuki agreed that the Supreme War Council should meet the next day. [59a]

Document 67B

Takashi Itoh, ed., Sokichi Takagi: Nikki to Joho [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 923-924 [Translation by Hikaru Tajima]

Document 68

Document 69

Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 5-9, 1945

Document 70

W.A. Harriman Papers, Library of Congress, box 211, Robert Pickens Meiklejohn World War II Diary At London and Moscow March 10, 1941-February 14, 1946, Volume II (Privately printed, 1980 [Printed from hand-written originals]) (Reproduced with permission)

Document 71

Documents 72A-C: The Attack on Nagasaki

Document 72A

RG 77, Tinian Files, April-December 1945, box 20, Envelope G Tinian Files, Top Secret

Document 72B

See description of document 72A.

Document 72C

Document 73A

Library of Congress, J. Robert Oppenheimer Papers, box 60, Ramsey, Norman

Document 73B

See description of document 73A.

Document 74

Document 75

Zenshiro Hoshina, Daitoa Senso Hishi: Hoshina Zenshiro Kaiso-roku [Secret History of the Greater East Asia War: Memoir of Zenshiro Hoshina] (Tokyo, Japan: Hara-Shobo, 1975), excerpts from Section 5, “The Emperor made go-seidan [= the sacred decision] – the decision to terminate the war,” 139-149 [translation by Hikaru Tajima]

Zenshiro Hoshina, a senior naval official, attended the conference and prepared a detailed account. With Prime Minister Suzuki presiding, each of the ministers had a chance to state their views directly to Hirohito. While Army Minister Anami tacitly threatened a coup (“civil war”), the emperor accepted the majority view that the reply to the Potsdam declaration should include only one condition not the four urged by “Big Six.” Nevertheless, the condition that Hirohito accepted was not the one that foreign minister Togo had brought to the conference. What was at stake was the definition of the kokutai (national policy). Togo’s proposal would have been generally consistent with a constitutional monarchy because it defined the kokutai narrowly as the emperor and the imperial household. What Hirohito accepted, however, was a proposal by the extreme nationalist Kiichiro Hiranuma which drew upon prevailing understandings of the kokutai : the “mythical notion” that the emperor was a living god. “This was the affirmation of the emperor’s theocratic powers, unencumbered by any law, based on Shinto gods in antiquity, and totally incompatible with a constitutional monarchy.” Thus, the Japanese response to the Potsdam declaration opposed “any demand which prejudices the prerogatives of his Majesty as a sovereign ruler.” This proved to be unacceptable to the Truman administration. [63]

Document 76

Document 77A

The first Japanese surrender offer was intercepted shortly before Tokyo broadcast it. This issue of the diplomatic summary also includes Togo’s account of his notification of the Soviet declaration of war, reports of Soviet military operations in the Far East, and intercepts of French diplomatic traffic.

Document 77B

A full translation of the surrender offer was circulated separately. The translations differ but they convey the sticking point that prevented U.S. acceptance: Tokyo’s condition that the allies not make any “demand which prejudices the prerogatives of His Majesty as a sovereign ruler.”

Document 78

Papers of Henry A. Wallace, Special Collections Department, University of Iowa Libraries, Iowa City, Iowa (copy courtesy of Special Collections Department)

Note: The second page of the diary entry includes a newspaper clipping of the Associated Press’s transmission of the Byrnes note. Unfortunately, AP would not authorize the Archive to reproduce this item without payment. Therefore, we are publishing an excised version of the entry, with a link to the Byrnes note .

Document 79

Document 80

Stimson’s account of the events of 10 August focused on the debate over the reply to the Japanese note, especially the question of the Emperor’s status. The U.S. reply , drafted during the course of the day, did not explicitly reject the note but suggested that any notion about the “prerogatives” of the Emperor would be superceded by the concept that all Japanese would be “Subject to the Supreme Commander of the Allied Powers.” The language was ambiguous enough to enable Japanese readers, upon Hirohito’s urging, to believe that they could decide for themselves the Emperor’s future role. Stimson accepted the language believing that a speedy reply to the Japanese would allow the United States to “get the homeland into our hands before the Russians could put in any substantial claim to occupy and help rule it.” If the note had included specific provision for a constitutional monarchy, Hasegawa argues, it would have “taken the wind out of the sails” of the military faction and Japan might have surrendered several days earlier, on August 11 or 12 instead of August 14. [65]

Document 81

Clemson University Libraries, Special Collections, Clemson, SC; Mss 243, Walter Brown Papers, box 68, folder 13, “Transcript/Draft B

Brown recounted Byrnes’ debriefing of the 10 August White House meeting on the Japanese peace offer, an account which differed somewhat from that in the Stimson diary. According to what Byrnes told Brown, Truman, Stimson, and Leahy favored accepting the Japanese note, but Byrnes objected that the United States should “go [no] further than we were willing to go at Potsdam.” Stimson’s account of the meeting noted Byrnes’ concerns (“troubled and anxious”) about the Japanese note and implied that he (Stimson) favored accepting it, but did not picture the debate as starkly as Browns's did.

Document 82

George C. Marshall Papers, George C. Marshall Library, Lexington, VA (copy courtesy of Barton J. Bernstein)

Groves informed General Marshall that he was making plans for the use of a third atomic weapon sometime after 17 August, depending on the weather. With Truman having ordered a halt to the atomic bombings [See document 78], Marshall wrote on Grove's memo that the bomb was “not to be released over Japan without express authority from the President.”

Document 83

Library of Congress Manuscript Division, Papers of W. Averell Harriman, box 181, Chron File Aug 10-12, 1945

Document 84

Takashi Itoh, ed., Sokichi Takagi: Nikki to Joho [Sokichi Takagi: Diary and Documents] (Tokyo, Japan: Misuzu-Shobo, 2000), 926-927 [Translation by Hikaru Tajima]

Document 85

National Archives, RG 165, Army Operations OPD, Executive Files 1940-1945, box 12, Exec #2

Document 86

Gaimusho [Ministry of Foreign Affairs], ed., Shusen Shiroku [Historical Record of the End of the War] (Tokyo: Hokuyosha, 1977-1978), vol. 5, 27-35 [Translated by Toshihiro Higuchi]

The Byrnes Note did not break the stalemate at the cabinet level. An account of the cabinet debates on August 13 prepared by Information Minister Toshiro Shimamura showed the same divisions as before; Anami and a few other ministers continued to argue that the Allies threatened the kokutai and that setting the four conditions (no occupation, etc.) did not mean that the war would continue. Nevertheless, Anami argued, “We are still left with some power to fight.” Suzuki, who was working quietly with the peace party, declared that the Allied terms were acceptable because they gave a “dim hope in the dark” of preserving the emperor. At the end of the meeting, he announced that he would report to Hirohito and ask him to make another “Sacred Judgment”. Meanwhile, junior Army officers plotted a coup to thwart the plans for surrender. [68]

Document 87

George C. Marshall Library, Lexington, VA, George C. Marshall Papers (copy courtesy of Barton J. Bernstein)

Document 88

Document 89

Hiroshi [Kaian) Shimomura, Shusenki [Account of the End of the War] (Tokyo, Kamakura Bunko, [1948], 148-152 [Translated by Toshihiro Higuchi]

Frightened by the rapid movement of Soviet forces into Manchuria and worried that the army might launch a coup, the peace party set in motion a plan to persuade Hirohito to meet with the cabinet and the “Big Six” to resolve the stalemate over the response to the Allies. Japan was already a day late in responding to the Byrnes Note and Hirohito agreed to move quickly. At 10:50 a.m., he met with the leadership at the bomb shelter in his palace. This account, prepared by Director of Information Shimomura, conveys the drama of the occasion (as well as his interest in shifting the blame for the debacle to the Army). After Suzuki gave the war party--Umeda, Toyoda, and Anami--an opportunity to present their arguments against accepting the Byrnes Note, he asked the emperor to speak.

Hirohito asked the leadership to accept the Note, which he believed was “well intentioned” on the matter of the “national polity” (by leaving open a possible role for the Emperor). Arguing that continuing the war would reduce the nation “to ashes,” his words about “bearing the unbearable” and sadness over wartime losses and suffering prefigured the language that Hirohito would use in his public announcement the next day. According to Bix, “Hirohito's language helped to transform him from a war to a peace leader, from a cold, aloof monarch to a human being who cared for his people” but “what chiefly motivated him … was his desire to save a politically empowered throne with himself on it.” [70]

Hirohito said that he would make a recording of the surrender announcement so that the nation could hear it. That evening army officers tried to seize the palace and find Hirohito’s recording, but the coup failed. Early the next day, General Anami committed suicide. On the morning of August 15, Hirohito broadcast the message to the nation (although he never used the word “surrender”). A few weeks later, on September 2, 1945 Japanese representatives signed surrender documents on the USS Missouri , in Tokyo harbor. [71]

Document 90

Document 91

The British National Archives, Records of the Foreign and Commonwealth Office, FO 800/461

With the Japanese surrender announcement not yet in, President Truman believed that another atomic bombing might become necessary. After a White House meeting on 14 August, British Minister John Balfour reported that Truman had “remarked sadly that he now had no alternative but to order an atomic bomb to be dropped on Tokyo.” This was likely emotional thinking spurred by anxiety and uncertainty. Truman was apparently not considering the fact that Tokyo was already devastated by fire bombing and that an atomic bombing would have killed the Emperor, which would have greatly complicated the process of surrender. Moreover, he may not have known that the third bomb was still in the United States and would not be available for use for nearly another week. [73] As it turned out, a few hours later, at 4:05 p.m., the White House received the Japanese surrender announcement.

Document 92

Department of Energy Open-Net

Two scientists at Oak Ridge’s Health Division, Henshaw and Coveyou, saw a United Press report in the Knoxville News Sentinel about radiation sickness caused by the bombings. Victims who looked healthy weakened, “for unknown reasons” and many died. Lacking direct knowledge of conditions in Hiroshima and Nagasaki, Henshaw and Coveyou had their own data on the biological effects of radiation and could make educated guesses. After reviewing the impact of various atomic bomb effects--blast, heat, flash radiation (prompt effects from gamma and neutron radiation), and radiation from radioactive substances--they concluded that “it seems highly plausible that a great many persons were subjected to lethal and sub-lethal dosages of radiation in areas where direct blast effects were possibly non-lethal.” It was “probable,” therefore, that radiation “would produce increments to the death rate and “even more probable” that a “great number of cases of sub-lethal exposures to radiation have been suffered.” [74]

Document 93

RG 77, MED Records, Top Secret Documents, File no. 5b

Document 94A

RG 77, Tinian Files, April-December 1945, box 17, Envelope B

See description of document 94B

Document 94B

XII. Eisenhower and McCloy’s Views on the Bombings and Atomic Weapons

Document 95

Document 96

Harry S. Truman Library, President's Secretary's Files, Speech Files, 1945-1953, copy on U.S. National Archives Web Site

On 15 December, President Truman spoke about the atomic bombings in his speech at the annual dinner of the Gridiron Club, organized by bureau chiefs and other leading figures of print media organizations. Besides Truman, guests included New York Governor Thomas Dewey (Republican presidential candidate in 1944 and 1948), foreign ambassadors, members of the cabinet and the Supreme Court, the military high command, and various senators and representatives. The U.S. Marine Band provided music for the dinner and for the variety show that was performed by members of the press. [79]

Truman characterized the Potsdam Declaration as a “fair warning,” but it was an ultimatum. Plainly he was troubled by the devastation and suffering caused by the bombings, but he found it justifiable because it saved the lives of U.S. troops. His estimate of 250,000 U.S. soldiers spared far exceeded that made by General Marshall in June 1945, which was in the range of 31,000 (comparable to the Battle of Luzon) [See Document 26]. By citing an inflated casualty figure, the president was giving a trial run for the rationale that would become central to official and semi-official discourse about the bombings during the decades ahead. [80]

Despite Truman’s claim that he made “the most terrible” decision at Potsdam, he assigned himself more responsibility than the historical record supports. On the basic decision, he had simply concurred with the judgments of Stimson, Groves, and others that the bomb would be used as soon as it was available for military use. As for targeting, however, he had a more significant role. At Potsdam, Stimson raised his objections to targeting Japan’s cultural capital, Kyoto, and Truman supported the secretary’s efforts to drop that city from the target list [See Documents 47 and 48]. [81]

[1] . The World Wide Web includes significant documentary resources on these events. The Truman Library has published a helpful collection of archival documents , some of which are included in the present collection. A collection of transcribed documents is Gene Dannen’s “ Atomic Bomb: Decision .” For a print collection of documents, see Dennis Merrill ed.,  Documentary History of the Truman Presidency: Volume I: The Decision to Drop the Atomic Bomb on Japan  (University Publications of America, 1995). A more recent collection of documents, along with a bibliography, narrative, and chronology, is Michael Kort’s  The Columbia Guide to Hiroshima and the Bomb  (New York: Columbia University Press, 2007). An important  on-line collection focuses on the air-raids of Japanese cities and bases, providing valuable context for the atomic attacks.

[2] . For the early criticisms and their impact on Stimson and other former officials, see Barton J. Bernstein, “Seizing the Contested Terrain of Early Nuclear History: Stimson, Conant, and Their Allies Explain the Decision to Use the Atomic Bomb,”  Diplomatic History  17 (1993): 35-72, and James Hershberg,  James B. Conant: Harvard to Hiroshima and the Making of the Nuclear Age  (Stanford, Stanford University Press, 1995), 291-301.

For Stimson’s article, see “The Decision to Use the Atomic Bomb,”  Harper’s  194 (February 1947): 97-107. Social critic Dwight MacDonald published trenchant criticisms immediately after Hiroshima-Nagasaki; see  Politics Past: Essays in Political Criticism  (New York: Viking, 1972), 169-180.

[3] . The proposed script for the Smithsonian exhibition can be seen at Philipe Nobile,

Judgment at the Smithsonian  (New York: Matthews and Company, 1995), pp. 1-127. For reviews of the controversy, see Barton J. Bernstein, “The Struggle Over History: Defining the Hiroshima Narrative,” ibid., 128-256, and Charles T. O’Reilly and William A. Rooney,  The Enola Gay and The Smithsonian  (Jefferson, NC: McFarland and Company, 2005).

[4] . For the extensive literature, see the references in J. Samuel Walker , Prompt and Utter Destruction: Truman and the Use of Atomic Bombs against Japan,  Third Edition (Chapel Hill: University of North Carolina Press, 2016) at 131-136, as well as Walker’s, “Recent Literature on Truman’s Atomic Bomb Decision: A Search for Middle Ground,”  Diplomatic History  29 (April 2005): 311-334. For more recent contributions, see Sean Malloy,  Atomic Tragedy: Henry L. Stimson and the Decision to Use the Bomb Against Japan  (Ithaca: Cornell University Press, 2008), Andrew Rotter,  Hiroshima: The World's Bomb  (New York: Oxford, 2008), Campbell Craig and Sergey Radchenko,  The Atomic Bomb and the Origins of the Cold War  (New Haven, Yale University Press, 2008), Wilson D. Miscamble,  The Most Controversial Decision: Truman, the Atomic Bombs, and the Defeat of Japan  (New York: Cambridge University Press, 2011). Also important to take into account is John Dower’s extensive discussion of Hiroshima/Nagasaki in context of the U.S. fire-bombings of Japanese cities in  Cultures of War: Pearl Harbor/Hiroshima/9-11/Iraq  (New York, W. Norton, 2010), 163-285.

[5] . The editor particularly benefited from the source material cited in the following works: Robert S. Norris,  Racing for the Bomb: General Leslie S. Groves, The Manhattan Project’s Indispensable Man  (South Royalton, VT: Steerforth Press, 2002); Gar Alperovitz,  The Decision to Use the Bomb and the Architecture of an American Myth  (New York: Alfred E. Knopf, 1995); Richard B. Frank , Downfall: The End of the Imperial Japanese Empire  (New York: Random House, 1999), Martin Sherwin,  A World Destroyed: Hiroshima and the Origins of the Arm Race  (New York, Vintage Books, 1987), and as already mentioned, Hasegawa’s  Racing the Enemy: Stalin, Truman, and the Surrender of Japan  (Cambridge, Harvard University Press, 2005 ).  Barton J. Bernstein’s numerous articles in scholarly publications (many of them are listed in Walker’s assessment of the literature) constitute an invaluable guide to primary sources. An article that Bernstein published in 1995, “The Atomic Bombings Reconsidered,”  Foreign Affairs  74 (1995), 135-152, nicely summarizes his thinking on the key issues.   Noteworthy publications since 2015 include Michael D. Gordin and G. John Ikenberry, eds., The Age of Hiroshim a (Princeton: Princeton University Press, 2019); Sheldon Garon, “On the Transnational Destruction of Cities: What Japan and the United States Learned from the Bombing of Britain and Germany in the Second World War,” Past and Present 247 (2020): 235-271; Katherine E. McKinney, Scott Sagan, and Allen S. Weiner, “Why the Atomic Bombing of Hiroshima Would Be Illegal Today,” The Bulletin of the Atomic Scientist s 76 (2020); Gregg Mitchell, The Beginning or the End: How Hollywood and America Learned  to Stop Worrying and Love the Bomb (New York: The New Press, 2020); Steve Olson, The Apocalypse Factory: Plutonium and the Making of the Atomic Age (New York: W.W. Norton, 2020); Neil J. Sullivan, The Prometheus Bomb: The Manhattan Project and Government in the Dark  (Lincoln, NE: University of Nebraska Press/Potomac Books, 2016); Alex Wellerstein; Restricted Data: The History of Nuclear Secrecy in the United States,  (Chicago: University of Chicago Press, forthcoming, 2020), a memoir by a Hiroshima survivor, Taniguchi Sumitero, The Atomic  Bomb on My Back: A Life Story of Survival and Activism (Montpelier, VT: Rootstock Publishing, 2020), and a collection of interviews, Cynthia C. Kelly, ed., The Manhattan Project: The Birth of the Atomic Bomb in the Words of Its Creators, Eyewitnesses, and Historians (Black Dog & Leventhal, 2020).

[6] . Malloy (2008), 49-50. For more on the Uranium Committee, the decision to establish the S-1 Committee, and the overall context, see James G. Hershberg , James B. Conant: Harvard to Hiroshima and the Making of the Nuclear Age  (Stanford, Stanford University Press, 1995), 140-154.

[7] . Sean Malloy, “`A Very Pleasant Way to Die’: Radiation Effects and the Decision to Use the Atomic Bomb against Japan,”  Diplomatic History  36 (2012), especially 523. For an important study of how contemporary officials and scientists looked at the atomic bomb prior to first use in Japan, see Michael D. Gordin,  Five Days in August: How World War II Became a Nuclear War  (Princeton: Princeton University Press, 2007).

[8] . Norris, 169.

[9] . Malloy (2008), 57-58.

[10] . See also Norris, 362.

[11] . For discussion of the importance of this memorandum, see Sherwin, 126-127, and Hershberg , James B. Conant , 203-207.

[12] . Alperovitz, 662; Bernstein (1995), 139; Norris, 377.

[13] . Quotation and statistics from Thomas R. Searle, “`It Made a Lot of Sense to Kill Skilled Workers’: The Firebombing of Tokyo in March 1945,  The Journal of Military History  55 (2002):103. More statistics and a detailed account of the raid is in Ronald Schaffer,  Wings of Judgment: American Bombing in World War II  (New York: Oxford University Press, 1985), 130-137.

[14] . Searle, “`It Made a Lot of Sense to Kill Skilled Workers,’” 118. For detailed background on the Army Air Force’s incendiary bombing planning, see Schaffer (1985) 107-127. On Stimson, see Schaffer (1985), 179-180 and Malloy (2008), 54. For a useful discussion of the firebombing of Tokyo and the atomic bombings, see Alex Wellerstein, “Tokyo vs. Hiroshima,”  Restricted Data: The Nuclear Secrecy Blog ,  22 September 2014

[15] . See for example, Bernstein (1995), 140-141.

[16] . For useful discussion of this meeting and the other Target Committee meetings, see Norris, 382-386.

[17] . Malloy, “A Very Pleasant Way to Die,” 531-534.

[18] . Schaffer,  Wings of Judgment , 143-146.

[19] . Alperovitz argues that the possibility of atomic diplomacy was central to the thinking of Truman and his advisers, while Bernstein, who argues that Truman’s primary objective was to end the war quickly, suggests that the ability to “cow other nations, notably the Soviet Union” was a “bonus” effect. See Bernstein (1995), 142.

[20] . Alperovitz, 147; Robert James Maddox,  Weapons for Victory: The Hiroshima Decision Fifty Years Later  (Columbia: University of Missouri Press, 1995), 52; Gabiel Kolko,  The Politics of War: The World and United States Foreign Policy, 1943-1945  (New York: Pantheon Books, 1990), 421-422. As Alperovitz notes, the Davies papers include variant diary entries and it is difficult to know which are the most accurate.

[21] . Malloy (2008), 112

[21A] . Vincent Jones, Manhattan: The Army and the Atomic Bomb (Washington, D.C.: U.S. Army Center of Military History, 1985), 529.

[22] . Bernstein (1995), 146. See also Barton J. Bernstein, “Looking Back: Gen. Marshall and the Atomic Bombing of Japanese Cities,” Arms Control Today , November 2015.

[23] . Bernstein (1995), 144. See also Malloy (2008), at 116-117, including the argument that 1) Stimson was deceiving himself by accepting the notion that a “vital war plant …surrounded by workers’ houses” was a legitimate military target, and 2) that Groves was misleading Stimson by withholding the Target Committee’s conclusions that the target would be a city center.

[24] . Walker (2005), 320.

[25] . Frank Costigliola,  France and the United States: The Cold Alliance Since World War II  (New York, Twayne, 1992), 38-39.

[26] . Barton J. Bernstein, Introduction to Helen S. Hawkins et al. editors,  Toward a Livable World: Leo Szilard and the Crusade for Nuclear Arms Control  (Cambridge: MIT Press, 1987), xxx-xxv; Sherwin, 210-215.

[27] . Herbert P. Bix,  Hirohito and the Making of Modern Japan  (New York: HarperCollins Publishers, 2000), 523.

[28] . Walker (2005), 319-320.

[29] . For a review of the debate on casualty estimates, see Walker (2005), 315, 317-318, 321, 323, and 324-325.

[30] . Hasegawa, 105; Alperovitz, 67-72; Forrest Pogue,  George C. Marshall: Statesman, 1945-1959  (New York: Viking, 1987), 18. Pogue only cites the JCS transcript of the meeting; presumably, an interview with a participant was the source of the McCloy quote.

[31] . Alperovitz, 226; Bernstein, “Understanding the Atomic Bomb and the Japanese Surrender,”  Diplomatic History  19 (1995), 237, note 22.

[32] . Malloy (2008), 123-124.

[33] . Alperovitz, 242, 245; Frank, 219.

[34] . Malloy (2008), 125-127.

[35] . Bernstein, introduction,  Toward a Livable World , xxxvii-xxxviii.

[36] . “Magic” summaries for post-August 1945 remain classified at the National Security Agency. Information from the late John Taylor, National Archives. For background on Magic and the “Purple” code, see John Prados,  Combined Fleet Decoded: The Secret History of American Intelligence and the Japanese Navy in World War II (  New York: Random House, 1995), 161-172 and David Kahn,  The Codebreakers: The Story of Secret Writing  (New York: Scribner, 1996), 1-67.

[37] . Alperovitz, 232-238.

[38] . Maddox, 83-84; Hasegawa, 126-128. See also Walker (2005), 316-317.

[39] . Hasegawa, 28, 121-122.

[40] . Peter Grose,  Gentleman Spy: The Life of Allen Dulles  (Boston: Houghton Mifflin, 1994), 170-174, 248-249.

[41] . David Holloway, “Barbarossa and the Bomb: Two Cases of Soviet Intelligence in World War II,” in Jonathan Haslam and Karina Urbach, eds.,  Secret Intelligence in the European States System, 1918-1989  (Stanford: Stanford University Press, 2014), 63-64. For the inception of the Soviet nuclear program and the role of espionage in facilitating it, see Holloway,  Stalin and the Bomb  (New Haven, Yale University Press, 1994).

[42] . For the distances, see Norris, 407.

[43] . For on-line resources on the first atomic test .

[44] . Bernstein’s detailed commentary on Truman’s diary has not been reproduced here except for the opening pages where he provides context and background.

[45] . Frank, 258; Bernstein (1995), 147; Walker (2005), 322. See also Alex Wellerstein’s “ The Kyoto Misconception ”

[46] . Maddox, 102; Alperovitz, 269-270; Hasegawa, 152-153.

[47] . Hasegawa, 292.

[48] . Bernstein, “Understanding the Atomic Bomb and the Japanese Surrender,”  Diplomatic History  19 (1995), 146-147; Alperovitz, 415; Frank, 246.

[49] . Alperovitz, 392; Frank, 148.

[50] . Alperovitz, 281-282. For Davies at Potsdam, see Elizabeth Kimball MacLean,  Joseph E. Davies: Envoy to the Soviets  (Westport, CT: Praeger, 1992), 151-166

[51] . Hasegawa, 168; Bix, 518.

[52] . Bix, 490, 521.

[53] . Alperovitz, 415; Frank, 246.

[54] . Frank, 273-274; Bernstein, “The Alarming Japanese Buildup on Southern Kyushu, Growing U.S. Fears and Counterfactual Analysis: Would the Planned November 1945 Invasion of Southern Kyushu Have Occurred?”  Pacific Historical Review  68 (1999): 561-609.

[55] . Maddox, 105.

[56] . Barton J. Bernstein, "'Reconsidering the 'Atomic General': Leslie R. Groves,"  The Journal of Military History  67 (July 2003): 883-920. See also Malloy, “A Very Pleasant Way to Die,” 539-540.

[57] . For casualty figures and the experience of people on the ground, see Frank, 264-268 and 285-286, among many other sources. Drawing on contemporary documents and journals, Masuji Ibuse’s novel  Black Rain  (Tokyo, Kodansha, 1982) provides an unforgettable account of the bombing of Hiroshima and its aftermath. For early U.S. planning to detonate the weapon at a height designed to maximize destruction from mass fires and other effects, see Alex Wellerstein, “ The Height of the Bomb .”

[58] . Sadao Asada, “The Shock of the Atomic Bomb and Japan’s Decision to Surrender: A Reconsideration,”  Pacific Historical Review  67 (1998): 101-148; Bix, 523; Frank, 348; Hasegawa, 298. Bix appears to have moved toward a position close to Hasegawa’s; see Bix, “Japan's Surrender Decision and the Monarchy: Staying the Course in an Unwinnable War,”  Japan Focus  . For emphasis on the “shock” of the atomic bomb, see also Lawrence Freedman and Saki Dockrill, “Hiroshima: A Strategy of Shock,” in Saki Dockrill, ed.,  From Pearl Harbor to Hiroshima : the Second World War in Asia and the Pacific, 1941-1945  (New York, St. Martin’s Press, 1994), 191-214. For more on the debate over Japan’s surrender, see Hasegawa’s important edited book,  The End of the Pacific War: A Reappraisal  (Stanford: Stanford University Press, 2007), with major contributions by Hasegawa, Holloway, Bernstein, and Hatano.

[59] . Melvyn P. Leffler, “Adherence to Agreements: Yalta and the Experiences of the Early Cold War,”  International Security  11 (1986): 107; Holloway, “Barbarossa and the Bomb,” 65.

[59a] . For more on these developments, see Asada, "The Shock of the Atomic Bomb and Japan's Decision to Surrender: A Reconsideration," 486-488.

[60] . Hasegawa, 191-192.

[61] . Frank, 286-287; Sherwin, 233-237; Bernstein (1995), 150; Maddox, 148.

[62] . The Supreme War Council comprised the prime minister, foreign minister, army and navy ministers, and army and navy chiefs of staff; see Hasegawa, 72 .

[63] . For the maneuverings on August 9 and the role of the  kokutai , see Hasegawa, 3-4, 205-214

[64] . For Truman’s recognition of mass civilian casualties, see also his  letter to Senator Richard Russell, 9 August 1945.

[65] . Hasegawa, 295.

[66] . For “tug of war,” see Hasegawa, 226-227.

[67] . Hasegawa, 228-229, 232.

[68] . Hasegawa, 235-238.

[69] . Barton J. Bernstein, “Eclipsed by Hiroshima and Nagasaki: Early Thinking about Tactical Nuclear Weapons,”  International Security  15 (Spring 1991): 149-173; Marc Gallicchio, “After Nagasaki: General Marshall’s Plans for Tactical Nuclear Weapons in Japan,”  Prologue  23 (Winter 1991): 396-404. Letters from Robert Messer and Gar Alperovitz, with Bernstein’s response, provide insight into some of the interpretative issues. “Correspondence,”  International Security  16 (Winter 1991/1992): 214-221.

[70] . Bix, “Japan's Surrender Decision and the Monarchy: Staying the Course in an Unwinnable War,”  Japan Focus .

[71] . For Hirohito' surrender speech--the actual broadcast and a translation--see  Japan Times , August 2015.

[72] . Cited by Barton J. Bernstein, “Eclipsed by Hiroshima and Nagasaki: Early Thinking About Tactical Nuclear Weapons,”  International Security  15 (1991) at page 167. Thanks to Alex Wellerstein for the suggestion and the archival link.

[73] . For further consideration of Tokyo and more likely targets at the time, see Alex Wellerstein, “Neglected Niigata,”  Restricted Data: The Nuclear Secrecy Blog, 9 October 2015.

[74] . See Malloy, “A Very Pleasant Way to Die,” 541-542.

[75] . For Groves and the problem of radiation sickness, see Norris, 339-441, Bernstein, “Reconsidering the ‘Atomic General’: Leslie R. Groves,”  Journal of Military History  67 (2003), 907-908, and Malloy, “A Very Pleasant Way to Die,” 513-518 and 539-542

[76] . See Janet Farrell Brodie, “Radiation Secrecy and Censorship after Hiroshima and Nagasaki,”  The Journal of Social History  48 (2015): 842-864.

[77] . For Eisenhower’s statements, see  Crusade in Europe  (Garden City: Doubleday, 1948), 443, and  Mandate for Change  (Garden City: Doubleday, 1963), 312-313. Barton J. Bernstein’s 1987 article, “Ike and Hiroshima: Did He Oppose It?”  The Journal of Strategic Studies  10 (1987): 377-389, makes a case against relying on Eisenhower’s memoirs and points to relevant circumstantial evidence. For a slightly different perspective, see Malloy (2007), 138

[78] . Cited in Barton J. Bernstein, “Truman and the A-Bomb: Targeting Noncombatants, Using the Bomb, and His Defending the "Decision,”  The Journal of Military History  62 (1998), at page 559. Thanks to Alex Wellerstein for the suggestion and the archival link.

[79] . “Truman Plays Part of Himself in Skit at Gridiron Dinner,” and “List of Members and Guests at the Gridiron Show,”  The Washington Post , 16 December 1945.

[80] . For varied casualty figures cited by Truman and others after the war, see Walker,  Prompt and Utter Destruction: Truman and the Use of Atomic Bombs Against Japan , 101-102.

[81] . See also ibid., 59.

The Devastating Effects of Nuclear Weapons

What can nuclear weapons do? How do they achieve their destructive purpose? What would a nuclear war — and its aftermath — look like? In the article that follows, excerpted from Richard Wolfson and Ferenc Dalnoki-Veress’s book “ Nuclear Choices for the Twenty-First Century ,” the authors explore these and related questions that reveal the most horrifying realities of nuclear war.

A Bomb Explodes: Short-Term Effects

The most immediate effect of a nuclear explosion is an intense burst of nuclear radiation, primarily gamma rays and neutrons. This direct radiation is produced in the weapon’s nuclear reactions themselves, and lasts well under a second. Lethal direct radiation extends nearly a mile from a 10-kiloton explosion. With most weapons, though, direct radiation is of little significance because other lethal effects generally encompass greater distances. An important exception is the enhanced-radiation weapon, or neutron bomb, which maximizes direct radiation and minimizes other destructive effects.

An exploding nuclear weapon instantly vaporizes itself. What was cold, solid material microseconds earlier becomes a gas hotter than the Sun’s 15-million-degree core. This hot gas radiates its energy in the form of X-rays, which heat the surrounding air. A fireball of superheated air forms and grows rapidly; 10 seconds after a 1-megaton explosion, the fireball is a mile in diameter. The fireball glows visibly from its own heat — so visibly that the early stages of a 1-megaton fireball are many times brighter than the Sun even at a distance of 50 miles. Besides light, the glowing fireball radiates heat.

This thermal flash lasts many seconds and accounts for more than one-third of the weapon’s explosive energy. The intense heat can ignite fires and cause severe burns on exposed flesh as far as 20 miles from a large thermonuclear explosion. Two-thirds of injured Hiroshima survivors showed evidence of such flash burns. You can think of the incendiary effect of thermal flash as analogous to starting a fire using a magnifying glass to concentrate the Sun’s rays. The difference is that rays from a nuclear explosion are so intense that they don’t need concentration to ignite flammable materials.

The intense heat can ignite fires and cause severe burns on exposed flesh as far as 20 miles from a large thermonuclear explosion.

As the rapidly expanding fireball pushes into the surrounding air, it creates a blast wave consisting of an abrupt jump in air pressure. The blast wave moves outward initially at thousands of miles per hour but slows as it spreads. It carries about half the bomb’s explosive energy and is responsible for most of the physical destruction. Normal air pressure is about 15 pounds per square inch (psi). That means every square inch of your body or your house experiences a force of 15 pounds. You don’t usually feel that force, because air pressure is normally exerted equally in all directions, so the 15 pounds pushing a square inch of your body one way is counterbalanced by 15 pounds pushing the other way. What you do feel is overpressure , caused by a greater air pressure on one side of an object.

If you’ve ever tried to open a door against a strong wind, you’ve experienced overpressure. An overpressure of even 1/100 psi could make a door almost impossible to open. That’s because a door has lots of square inches — about 3,000 or more. So 1/100 psi adds up to a lot of pounds. The blast wave of a nuclear explosion may create overpressures of several psi many miles from the explosion site. Think about that! There are about 50,000 square inches in the front wall of a modest house — and that means 50,000 pounds or 25 tons of force even at 1 psi overpressure. Overpressures of 5 psi are enough to destroy most residential buildings. An overpressure of 10 psi collapses most factories and commercial buildings, and 20 psi will level even reinforced concrete structures.

People, remarkably, are relatively immune to overpressure itself. But they aren’t immune to collapsing buildings or to pieces of glass hurtling through the air at hundreds of miles per hour or to having themselves hurled into concrete walls — all of which are direct consequences of a blast wave’s overpressure. Blast effects therefore cause a great many fatalities. Blast effects depend in part on where a weapon is detonated. The most widespread damage to buildings occurs in an air burst , a detonation thousands of feet above the target. The blast wave from an air burst reflects off the ground, which enhances its destructive power. A ground burst , in contrast, digs a huge crater and pulverizes everything in the immediate vicinity, but its blast effects don’t extend as far. Nuclear attacks on cities would probably employ air bursts, whereas ground bursts would be used on hardened military targets such as underground missile silos. As you’ll soon see, the two types of blasts have different implications for radioactive fallout.

How far do a weapon’s destructive effects extend? That distance — the radius of destruction — depends on the explosive yield. The volume encompassing a given level of destruction depends directly on the weapon’s yield. Because volume is proportional to the radius cubed, that means the destructive radius grows approximately as the cube root of the yield. A 10-fold increase in yield then increases the radius of destruction by a factor of only a little over two. The area of destruction grows faster but still not in direct proportion to the yield. That relatively slow increase in destruction with increasing yield is one reason why multiple smaller weapons are more effective than a single larger one. Twenty 50-kiloton warheads, for example, destroy nearly three times the area leveled by a numerically equivalent 1-megaton weapon.

What constitutes the radius of destruction also depends on the level of destruction you want to achieve. Roughly speaking, though, the distance at which overpressure has fallen to about 5 psi is a good definition of destructive radius. Many of the people within this distance would be killed, although some wouldn’t. But some would be killed beyond the 5-psi distance, making the situation roughly equivalent to having everyone within the 5-psi circle killed and everyone outside surviving. The image to the left shows how the destructive zone varies with explosive yield for a hypothetical explosion. This is a simplified picture; a more careful calculation of the effects of nuclear weapons on entire populations requires detailed simulations that include many environmental and geographic variables.

The blast wave is over in a minute or so, but the immediate destruction may not be. Fires started by the thermal flash or by blast effects still rage, and under some circumstances they may coalesce into a single gigantic blaze called a firestorm that can develop its own winds and thus cause the fire to spread. Hot gases rise from the firestorm, replaced by air rushing inward along the surface at hundreds of miles per hour. Winds and fire compound the blast damage, and the fire consumes enough oxygen to suffocate any remaining survivors.

During World War II, bombing of Hamburg with incendiary chemicals resulted in a firestorm that claimed 45,000 lives. The nuclear bombing of Hiroshima resulted in a firestorm; that of Nagasaki did not, likely because of Nagasaki’s rougher terrain. The question of firestorms is important not only to the residents of a target area: Firestorms might also have significant long-term effects on the global climate, as we’ll discuss later.

Both nuclear and conventional weapons produce destructive blast effects, although of vastly different magnitudes. But radioactive fallout is unique to nuclear weapons. Fallout consists primarily of fission products, although neutron capture and other nuclear reactions contribute additional radioactive material. The term fallout generally applies to those isotopes whose half-lives exceed the time scale of the blast and other short-term effects. Although fallout contamination may linger for years and even decades, the dominant lethal effects last from days to weeks, and contemporary civil defense recommendations are for survivors to stay inside for at least 48 hours while the radiation decreases.

The fallout produced in a nuclear explosion depends greatly on the type of weapon, its explosive yield, and where it’s exploded. The neutron bomb, although it produces intense direct radiation, is primarily a fusion device and generates only slight fallout from its fission trigger. Small fission weapons like those used at Hiroshima and Nagasaki produce locally significant fallout. But the fission-fusion-fission design used in today’s thermonuclear weapons introduces the new phenomenon of global fallout . Most of this fallout comes from fission of the U-238 jacket that surrounds the fusion fuel. The global effect of these huge weapons comes partly from the sheer quantity of radioactive material and partly from the fact that the radioactive cloud rises well into the stratosphere, where it may take months or even years to reach the ground. Even though we’ve had no nuclear war since the bombings of Hiroshima and Nagasaki, fallout is one weapons effect with which we have experience. Atmospheric nuclear testing before the 1963 Partial Test Ban Treaty resulted in detectable levels of radioactive fission products across the globe, and some of that radiation is still with us.

Fallout differs greatly depending on whether a weapon is exploded at ground level or high in the atmosphere. In an air burst, the fireball never touches the ground, and radioactivity rises into the stratosphere. This reduces local fallout but enhances global fallout. In a ground burst, the explosion digs a huge crater and entrains tons of soil, rock, and other pulverized material into its rising cloud. Radioactive materials cling to these heavier particles, which drop back the ground in a relatively short time. Rain may wash down particularly large amounts of radioactive material, producing local hot spots of especially intense radioactivity. A hot spot in Albany, New York, thousands of miles from the 1953 Nevada test that produced it, exposed area residents to some 10 times their annual background radiation dose. The exact distribution of fallout depends crucially on wind speed and direction; under some conditions, lethal fallout may extend several hundred miles downwind of an explosion. However, it’s important to recognize that the lethality of fallout quickly decreases as short-lived isotopes decay.

Recommended Response to a Nuclear Explosion

The United States government has recently provided guidance on how to respond to a nuclear detonation. One recommendation is to divide the region of destruction due to blast effects into three separate damage zones. This division provides guidance for first responders in assessing the situation. Outermost is the light damage zone , characterized by “broken windows and easily managed injuries.” Next is the moderate damage zone with “significant building damage, rubble, downed utility lines and some downed poles, overturned automobiles, fires, and serious injuries.” Finally, there’s the severe damage zone , where buildings will be completely collapsed, radiation levels high, and survivors unlikely.

The recommendations also define a dangerous fallout zone spanning different structural damage zones. This is the region where dose rates exceed a whole-body external dose of about 0.1 Sv/hour. First responders must exercise special precautions as they approach the fallout zone in order to limit their own radiation exposure. The dangerous fallout zone can easily stretch 10 to 20 miles (15 to 30 kilometers) from the detonation depending on explosive yield and weather conditions.

Electromagnetic Pulse

A nuclear weapon exploded at very high altitude produces none of the blast or local fallout effects we’ve just described. But intense gamma rays knock electrons out of atoms in the surrounding air, and when the explosion takes place in the rarefied air at high altitude this effect may extend hundreds of miles. As they gyrate in Earth’s magnetic field, the electrons generate an intense pulse of radio waves known as an electromagnetic pulse (EMP).

A single large weapon exploded some 200 miles over the central United States could blanket the entire country with an electromagnetic pulse intense enough to damage computers, communication systems, and other electronic devices. It could also affect satellites used for military communications, reconnaissance, and attack warning. The EMP phenomenon thus has profound implications for a military that depends on sophisticated electronics. In 1962, the United States detonated a 1.4-megaton warhead 250 miles above Johnston Island in the Pacific Ocean. People as far as Australia and New Zealand witnessed the explosion as a red aurora appearing in the night sky. Hawaiians, only 800 miles from the island, experienced a bright flash followed by a green sky and the failure of hundreds of street lights. In total, the Soviet Union and the United States conducted 20 tests of EMP from nuclear detonations. However, it’s unclear how to extrapolate the results to today’s more sensitive and more pervasive electronic equipment.

Since the Partial Test Ban Treaty of 1963 it has been virtually impossible to study EMP effects directly, although elaborate devices have been developed to mimic the electronic impact of nuclear weapons. Increasingly, crucial electronic systems are “hardened” to minimize the impact of EMP. Nevertheless, the use of EMP in a war could wreak havoc with systems for communication and control of military forces.

Many countries are around the world are developing high-powered microwave weapons which, although not nuclear devices, are designed to produce EMPs. These directed-energy weapons , also called e-bombs , emit large pulses of microwaves to destroy electronics on missiles, to stop cars, to detonate explosives remotely, and to down swarms of drones. Despite these EMP weapons being nonlethal in the sense that there’s no bang or blast wave, an enemy may be unable to distinguish their effects from those of nuclear weapons.

Would the high-altitude detonation of a nuclear weapon to produce EMP or the use of a directed-beam EMP weapon be an act of war warranting nuclear retaliation? With its electronic warning systems in disarray, should the EMPed nation launch a nuclear strike on the chance that it was about to be attacked? How are nuclear decisions to be made in a climate of EMP-crippled communications? These are difficult questions, but military strategists need to have answers.

Nuclear War

So far we’ve examined the effects of single nuclear explosions. But a nuclear war would involve hundreds to thousands of explosions, creating a situation for which we simply have no relevant experience. Despite decades of arms reduction treaties, there are still thousands of nuclear weapons in the world’s arsenals. Detonating only a tiny fraction of these would cause mass casualties.

What would a nuclear war be like? When you think of nuclear war, you probably envision an all-out holocaust in which adversaries unleash their arsenals in an attempt to inflict the most damage. Many people — including your authors — believe that misfortune to be the likely outcome of almost any use of nuclear weapons among the superpowers. But nuclear strategists have explored many scenarios that fall short of the all-out nuclear exchange. What might these limited nuclear wars be like? Could they really remain limited ?

Limited Nuclear War

One form of limited nuclear war would be like a conventional battlefield conflict but using low-yield tactical nuclear weapons. Here’s a hypothetical scenario: After its 2014 annexation of Crimea, Russia attacks a Baltic country with tanks and ground forces while the United States is distracted by a domestic crisis. NATO responds with decisive counterforce, destroying Russian tanks with fighter jets, but this doesn’t quell Russian resolve. Russia responds with even more tanks and by bombing NATO installations, killing several hundred troops. NATO cannot tolerate such aggression and to prevent further Russian advance launches low-yield tactical nuclear weapons with their dial-a-yield positions set to the lowest settings of only 300 tons TNT equivalent. The goal is to signal Russia that it has crossed a line and to deescalate the situation. NATO’s actions are based on fear that if the Russian aggression weren’t stopped the result would be all-out war in northern Europe.

This strategy is actually being discussed in the higher echelons of the Pentagon. The catchy concept is that use of a few low-yield nuclear weapons could show resolve, with the hoped-for outcome that the other party will back down from its aggressive behavior (this concept is known as escalate to deescalate ). The assumption is that the nuclear attack would remain limited, that parties would go back to the negotiating table, and that saner voices would prevail. However, this assumes a chain of events where everything unfolds as expected. It neglects the incontrovertible fact that, as the Prussian general Carl von Clausewitz observed in the 19th century, “Three quarters of the factors on which action in war is based are wrapped in a fog of greater or lesser uncertainty.” Often coined fog of war , this describes the lack of clarity in wartime situations on which decisions must nevertheless be based. In the scenario described, sensors could have been damaged or lines of communication severed that would have reported the low-yield nature of the nuclear weapons. As a result, Russia might feel its homeland threatened and respond with an all-out attack using strategic nuclear weapons, resulting in millions of deaths.

There is every reason to believe that a limited nuclear war wouldn’t remain limited.

There is every reason to believe that a limited nuclear war wouldn’t remain limited. A 1983 war game known as Proud Prophet involved top-secret nuclear war plans and had as participants high-level decision makers including President Reagan’s Secretary of Defense Caspar Weinberger. The war game followed actual plans but unexpectedly ended in total nuclear annihilation with more than half a billion fatalities in the initial onslaught — not including subsequent deaths from starvation. The exercise revealed that a limited nuclear strike may not achieve the desired results! In this case, that was because the team playing the Soviet Union responded to a limited U.S. nuclear strike with a massive all-out nuclear attack.

What about an attack on North Korea? In 2017, some in the U.S. cabinet advocated for a “bloody nose” strategy in dealing with North Korea’s flagrant violations of international law. This is the notion that in response to a threatening action by North Korea, the U.S. would destroy a significant site to “bloody Pyongyang’s nose.” This might employ a low-yield nuclear attack or a conventional attack. The “bloody nose” strategy relies on the expectation that Pyongyang would be so overwhelmed by U.S. might that they would immediately back down and not retaliate. However, North Korea might see any type of aggression as an attack aimed at overthrowing their regime, and could retaliate with an all-or-nothing response using weapons of mass destruction (including but not necessarily limited to nuclear weapons) as well as their vast conventional force.

In September 2017, during the height of verbal exchanges between President Trump and the North Korean dictator Kim Jong-un, the U.S. flew B-1B Lancer bombers along the North Korean coast, further north of the demilitarized zone than the U.S. had ever done, while still staying over international waters. However, North Korea didn’t respond at all, making analysts wonder whether the bombers were even detected. Uncertainty in North Korea’s ability to discriminate different weapon systems might exacerbate a situation like this one and could lead the North Koreans viewing any intrusion as an “attack on their nation, their way of life and their honor.” This is exactly how the Soviet team in the Proud Prophet war game interpreted it.

What about a limited attack on the United States? Suppose a nuclear adversary decided to cripple the U.S. nuclear retaliatory forces (a virtual impossibility, given nuclear missile submarines, but a scenario considered with deadly seriousness by nuclear planners). Many of the 48 contiguous states have at least one target — a nuclear bomber base, a submarine support base, or intercontinental missile silos — that would warrant destruction in such an attack. The attack, which would require only a tiny fraction of the strategic nuclear weapons in the Russian arsenal, could kill millions of civilians. Those living near targeted bomber and submarine bases would suffer blast and local radiation effects. Intense fallout from ground-burst explosions on missile silos in the Midwest would extend all the way to the Atlantic coast. Fallout would also contaminate a significant fraction of U.S. cropland for up to year and would kill livestock. On the other hand, the U.S. industrial base would remain relatively unscathed, if no further hostilities occurred.

In contrast to attacking military targets, an adversary might seek to cripple the U.S. economy by destroying a vital industry. In one hypothetical attack considered by the congressional Office of Technology Assessment, ten Soviet SS-18 missiles, each with eight 1-megaton warheads, attack United States’ oil refineries. The result is destruction of two-thirds of the U.S. oil-refining capability. And even with some evacuation of major cities in the hypothetical crisis leading to the attack, 5 million Americans are killed.

Each of these “limited” nuclear attack scenarios kills millions of Americans — many, many times the 1.2 million killed in all the wars in our nation’s history. Do we want to entertain limited nuclear war as a realistic possibility? Do we believe nuclear war could be limited to “only” a few million casualties? Do we trust the professional strategic planners who prepare our possible nuclear responses to an adversary’s threats? What level of nuclear preparedness do we need to deter attack?

All-Out Nuclear War

Whether from escalation of a limited nuclear conflict or as an outright full-scale attack, an all-out nuclear war remains possible as long as nuclear nations have hundreds to thousands of weapons aimed at one another. What would be the consequences of all-out nuclear war?

Within individual target cities, conditions described earlier for single explosions would prevail. (Most cities, though, would likely be targeted with multiple weapons.) Government estimates suggest that over half of the United States’ population could be killed by the prompt effects of an all-out nuclear war. For those within the appropriate radii of destruction, it would make little difference whether theirs was an isolated explosion or part of a war. But for the survivors in the less damaged areas, the difference could be dramatic.

Consider the injured. Thermal flash burns extend well beyond the 5-psi radius of destruction. A single nuclear explosion might produce 10,000 cases of severe burns requiring specialized medical treatment; in an all-out war there could be several million such cases. Yet the United States has facilities to treat fewer than 2,000 burn cases — virtually all of them in urban areas that would be leveled by nuclear blasts. Burn victims who might be saved, had their injuries resulted from some isolated cause, would succumb in the aftermath of nuclear war. The same goes for fractures, lacerations, missing limbs, crushed skulls, punctured lungs, and myriad other injuries suffered as a result of nuclear blast. Where would be the doctors, the hospitals, the medicines, the equipment needed for their treatment? Most would lie in ruin, and those that remained would be inadequate to the overwhelming numbers of injured. Again, many would die whom modern medicine could normally save.

A single nuclear explosion might produce 10,000 cases of severe burns requiring specialized medical treatment; in an all-out war there could be several million such cases.

In an all-out war, lethal fallout would cover much of the United States. Survivors could avoid fatal radiation exposure only when sheltered with adequate food, water, and medical supplies. Even then, millions would be exposed to radiation high enough to cause lowered disease resistance and greater incidence of subsequent fatal cancer. Lowered disease resistance could lead to death from everyday infections in a population deprived of adequate medical facilities. And the spread of diseases from contaminated water supplies, nonexistent sanitary facilities, lack of medicines, and the millions of dead could reach epidemic proportions. Small wonder that the international group Physicians for Social Responsibility has called nuclear war “the last epidemic.”

Attempts to contain damage to cities, suburbs, and industries would suffer analogously to the treatment of injured people. Firefighting equipment, water supplies, electric power, heavy equipment, fuel supplies, and emergency communications would be gone. Transportation into and out of stricken cities would be blocked by debris. The scarcity of radiation-monitoring equipment and of personnel trained to operate it would make it difficult to know where emergency crews could safely work. Most of all, there would be no healthy neighboring cities to call on for help; all would be crippled in an all-out war.

Is Nuclear War Survivable?

We’ve noted that more than half the United States’ population might be killed outright in an all-out nuclear war. What about the survivors?

Recent studies have used detailed three-dimensional, block-by-block urban terrain models to study the effects of 10-kiloton detonations on Washington, D.C. and Los Angeles. The results settle an earlier controversy about whether survivors should evacuate or shelter in place: Staying indoors for 48 hours after a nuclear blast is now recommended. That time allows fallout levels to decay by a factor of 100. Furthermore, buildings between a survivor and the blast can block the worst of the fallout, and going deep inside an urban building can lower fallout levels still further. The same shelter-in-place arguments apply to survivors in the non-urban areas blanketed by fallout.

These new studies, however, consider only single detonations as might occur in a terrorist or rogue attack. In considering all-out nuclear war, we have to ask a further question: Then what?

Individuals might survive for a while, but what about longer term, and what about society as a whole? Extreme and cooperative efforts would be needed for long-term survival, but would the shocked and weakened survivors be up to those efforts? How would individuals react to watching their loved ones die of radiation sickness or untreated injuries? Would an “everyone for themselves” attitude prevail, preventing the cooperation necessary to rebuild society? How would residents of undamaged rural areas react to the streams of urban refugees flooding their communities? What governmental structures could function in the postwar climate? How could people know what was happening throughout the country? Would international organizations be able to cope?

Staying indoors for 48 hours after a nuclear blast is now recommended. That time allows fallout levels to decay by a factor of 100.

Some students of nuclear war see postwar society in a race against time. An all-out war would have destroyed much of the nation’s productive capacity and would have killed many of the experts who could help guide social and physical reconstruction. The war also would have destroyed stocks of food and other materials needed for survival.

On the other hand, the remaining supplies would have to support only the much smaller postwar population. The challenge to the survivors would be to establish production of food and other necessities before the supplies left from before the war were exhausted. Could the war-shocked survivors, their social and governmental structure shattered, meet that challenge? That is a very big nuclear question — so big that it’s best left unanswered, since only an all-out nuclear war could decide it definitively.

Climatic Effects

A large-scale nuclear war would pump huge quantities of chemicals and dust into the upper atmosphere. Humanity was well into the nuclear age before scientists took a good look at the possible consequences of this. What they found was not reassuring.

The upper atmosphere includes a layer enhanced in ozone gas, an unusual form of oxygen that vigorously absorbs the Sun’s ultraviolet radiation. In the absence of this ozone layer , more ultraviolet radiation would reach Earth’s surface, with a variety of harmful effects. A nuclear war would produce huge quantities of ozone-consuming chemicals, and studies suggest that even a modest nuclear exchange would result in unprecedented increases in ultraviolet exposure. Marine life might be damaged by the increased ultraviolet radiation, and humans could receive blistering sunburns. More UV radiation would also lead to a greater incidence of fatal skin cancers and to general weakening of the human immune system.

Even more alarming is the fact that soot from the fires of burning cities after a nuclear exchange would be injected high into the atmosphere. A 1983 study by Richard Turco, Carl Sagan, and others (the so-called TTAPS paper) shocked the world with the suggestion that even a modest nuclear exchange — as few as 100 warheads — could trigger drastic global cooling as airborne soot blocked incoming sunlight. In its most extreme form, this nuclear winter hypothesis raised the possibility of extinction of the human species. (This is not the first dust-induced extinction pondered by science. Current thinking holds that the dinosaurs went extinct as a result of climate change brought about by atmospheric dust from an asteroid impact; indeed, that hypothesis helped prompt the nuclear winter research.)

The original nuclear winter study used a computer model that was unsophisticated compared to present-day climate models, and it spurred vigorous controversy among atmospheric scientists. Although not the primary researcher on the publication, Sagan lent his name in order to publicize the work. Two months before Science would publish the paper, he decided to introduce the results in the popular press. This backfired, as Sagan was derided by hawkish physicists like Edward Teller who had a stake in perpetuating the myth that nuclear war could be won and the belief that a missile defense system could protect the United States from nuclear attack. Teller called Sagan an “excellent propagandist” and suggested that the concept of nuclear winter was “highly speculative.” The damage was done, and many considered the nuclear winter phenomenon discredited.

But research on nuclear winter continued. Recent studies with modern climate models show that an all-out nuclear war between the United States and Russia, even with today’s reduced arsenals, could put over 150 million tons of smoke and soot into the upper atmosphere. That’s roughly the equivalent of all the garbage the U.S. produces in a year! The result would be a drop in global temperature of some 8°C (more than the difference between today’s temperature and the depths of the last ice age), and even after a decade the temperature would have recovered only 4°C. In the world’s “breadbasket” agricultural regions, the temperature could remain below freezing for a year or more, and precipitation would drop by 90 percent. The effect on the world’s food supply would be devastating.

Even a much smaller nuclear exchange could have catastrophic climate consequences. The research cited above also suggests that a nuclear exchange between India and Pakistan, involving 100 Hiroshima-sized weapons, would shorten growing seasons and threaten annual monsoon rains, jeopardizing the food supply of a billion people. The image below shows the global picture one month after this hypothetical 100-warhead nuclear exchange.

Nuclear weapons have devastating effects. Destructive blast effects extend miles from the detonation point of a typical nuclear weapon, and lethal fallout may blanket communities hundreds of miles downwind of a single nuclear explosion. An all-out nuclear war would leave survivors with few means of recovery, and could lead to a total breakdown of society. Fallout from an all-out war would expose most of the belligerent nations’ surviving populations to radiation levels ranging from harmful to fatal. And the effects of nuclear war would extend well beyond the warring nations, possibly including climate change severe enough to threaten much of the planet’s human population.

Debate about national and global effects of nuclear war continues, and the issues are unlikely to be decided conclusively without the unfortunate experiment of an actual nuclear war. But enough is known about nuclear war’s possible effects that there is near universal agreement on the need to avoid them. As the great science communicator and astronomer Carl Sagan once said, “It’s elementary planetary hygiene to clean the world of these nuclear weapons.” But can we eliminate nuclear weapons? Should we? What risks might such elimination entail? Those are the real issues in the ongoing debates about the future of nuclear weaponry.

Richard Wolfson is Benjamin F. Wissler Professor of Physics at Middlebury College. Ferenc Dalnoki-Veress is Scientist-in-Residence at the Center for Nonproliferation Studies of the Middlebury Institute of International Studies. This article is excerpted from their book “ Nuclear Choices for the Twenty-First Century: A Citizen’s Guide. “

air burst A nuclear explosion detonated at an altitude—typically, thousands of feet—that maximizes blast damage. Because its fireball never touches the ground, an air burst produces less radioactive fallout than a ground burst.

blast wave An abrupt jump in air pressure that propagates outward from a nuclear explosion, damaging or destroying whatever it encounters.

direct radiation Nuclear radiation produced in the actual detonation of a nuclear weapon and constituting the most immediate effect on the surrounding environment.

electromagnetic pulse (EMP) An intense burst of radio waves produced by a high-altitude nuclear explosion, capable of damaging electronic equipment over thousands of miles.

fallout Radioactive material, mostly fission products, released into the environment by nuclear explosions.

fireball A mass of air surrounding a nuclear explosion and heated to luminous temperatures.

firestorm A massive fire formed by coalescence of numerous smaller fires.

ground burst A nuclear explosion detonated at ground level, producing a crater and significant fallout but less widespread damage than an air burst.

nuclear difference Phrase we use to describe the roughly million-fold difference in energy released in nuclear reactions versus chemical reactions.

nuclear winter A substantial reduction in global temperature that might result from soot injected into the atmosphere during a nuclear war.

overpressure Excess air pressure encountered in the blast wave of a nuclear explosion. Overpressure of a few pounds per square inch is sufficient to destroy typical wooden houses.

radius of destruction The distance from a nuclear blast within which destruction is near total, often taken as the zone of 5-pound-per-square-inch overpressure.

thermal flash An intense burst of heat radiation in the seconds following a nuclear explosion. The thermal flash of a large weapon can ignite fires and cause third-degree burns tens of miles from the explosion.

• History & Society
• Science & Tech
• Biographies
• Animals & Nature
• Geography & Travel
• Arts & Culture
• Games & Quizzes
• On This Day
• One Good Fact
• New Articles
• Lifestyles & Social Issues
• Philosophy & Religion
• Politics, Law & Government
• World History
• Health & Medicine
• Browse Biographies
• Birds, Reptiles & Other Vertebrates
• Bugs, Mollusks & Other Invertebrates
• Environment
• Fossils & Geologic Time
• Entertainment & Pop Culture
• Sports & Recreation
• Visual Arts
• Demystified
• Image Galleries
• Infographics
• Top Questions
• Britannica Kids
• Saving Earth
• Space Next 50
• Student Center
• Introduction & Top Questions

Early atomic research

The american atomic program takes shape, from stagg field to los alamos, the trinity test, the bombing of hiroshima.

• The bombing of Nagasaki
• The Japanese surrender
• Casualties, damage, and the legacy of Hiroshima and Nagasaki

What were the atomic bombings of Hiroshima and Nagasaki?

Who was involved in the atomic bombings of hiroshima and nagasaki, why did the atomic bombings of hiroshima and nagasaki happen, what were the results of the atomic bombings of hiroshima and nagasaki.

• Why was Hiroshima bombed?

atomic bombings of Hiroshima and Nagasaki

Our editors will review what you’ve submitted and determine whether to revise the article.

• Atomic Heritage Foundation - Bombings of Hiroshima and Nagasaki - 1945
• World Nuclear Association - Hiroshima, Nagasaki, and Subsequent Weapons Testing
• Atomicarchive.com - The Atomic Bombings of Hiroshima and Nagasaki
• Live Science - The first atomic bombs: Hiroshima and Nagasaki
• Academia - Hiroshima and Nagasaki: a case of Unpunished War Crimes
• Table Of Contents

The atomic bombings of Hiroshima and Nagasaki were American bombing raids on the Japanese cities of Hiroshima and Nagasaki during World War II , which marked the first use of atomic weapons in war. Little Boy , the bomb dropped on Hiroshima , was a gun-assembly fission bomb using uranium , whereas Fat Man , the bomb dropped on Nagasaki , was an implosion fission bomb utilizing plutonium .

When were the atomic bombs dropped on Hiroshima and Nagasaki?

The first atomic bomb, named Little Boy , was dropped on Hiroshima from the Enola Gay , a B-29 bomber, at 8:15 AM on August 6, 1945. The second bomb, named Fat Man , was dropped on Nagasaki from the Bockscar , also a B-29 bomber, at 11:02 AM on August 9, 1945.

American physicist J. Robert Oppenheimer headed the Manhattan Project to develop atomic bombs for the United States, and Edward Teller was among the first scientists recruited for the project. Leo Szilard and Enrico Fermi built the first nuclear reactor. Ernest Orlando Lawrence was program chief in charge of the development of the electromagnetic process of separating uranium-235. The person who oversaw the project, however, was not a scientist. He was U.S. Army Brigadier General Leslie R. Groves . In all, more than one hundred thousand people were employed for the Manhattan Project. The bombings themselves were carried out by the pilot of the Enola Gay Colonel Paul Warfield Tibbets, Jr., and pilot of the Bockscar Major Charles W. Sweeney and their respective crews.

A number of factors contributed to the United States ’ decision to drop atomic bombs on Japan . One reason was Japan’s unwillingness to surrender unconditionally. Japan wanted to keep their emperor and conduct their own war trials and did not want to be occupied by U.S. forces. However, the United States wanted unconditional surrender, which thus meant the continuation of the war. Japan refused to surrender after multiple firebombing campaigns such as the Bombing of Tokyo on March 9–10, 1945. The Bombing of Tokyo alone claimed tens of thousands of lives and is often cited as one of the most destructive acts of war in history. Although the precise death toll is unknown, conservative estimates suggest that the firestorm caused by incendiary bombs killed at least 80,000 people, likely more than 100,000, in a single night; some one million people were left homeless. It looked increasingly likely that the United States would have to commit itself to a land invasion, which could have claimed many American lives. Instead, the atomic bomb served as a tool to bring the war in the Pacific to a close sooner.

Another reason why the United States dropped the atomic bombs—and, specifically, the second one on Nagasaki —has to do with the Soviet Union . On August 8, 1945, two days after the Hiroshima bombing, as agreed to by Joseph Stalin during the Tehrān and Yalta conferences in 1943 and 1945, respectively, the Soviet Union declared war on Japan. It is possible that U.S. President Harry Truman ordered the atomic bomb to be dropped on Nagasaki not only to further force Japan to surrender but also to keep the Soviets out of Japan by displaying American military power. Distrust and a sense of rivalry had been built up between the two superpowers that ultimately culminated in the Cold War .

The atomic bombings of Hiroshima and Nagasaki produced effects in Japan and around the world that changed the course of history. Tens of thousands of people were killed in the initial explosions (an estimated 70,000 in Hiroshima and 40,000 in Nagasaki), and many more later succumbed to burns, injuries, and radiation poisoning . On August 10, 1945, one day after the bombing of Nagasaki, the Japanese government issued a statement agreeing to accept the Allied surrender terms that had been dictated in the Potsdam Declaration . The United States gained wide-reaching influence in Japan during its occupation and as a result of its installation of the Supreme Commander for the Allied Powers, a title held by the American general Douglas MacArthur . The U.S. occupation of Japan had long and lasting effects on daily life in Japan as well as on Japan’s economy, military, and government.

The atomic bombings of Hiroshima and Nagasaki also caused global effects such as the Cold War and the proliferation of nuclear weapons around the world. The Cold War was a rivalry that saw the world’s two remaining superpowers after World War II—the United States and the Soviet Union , as well as their respective allies—fight for political, economic, and nuclear superiority. Today, more countries possess nuclear weapons, but such weapons have not been used in warfare since the bombings of Hiroshima and Nagasaki.

Recent News

atomic bombings of Hiroshima and Nagasaki , during World War II , American bombing raids on the Japanese cities of Hiroshima (August 6, 1945) and Nagasaki (August 9, 1945) that marked the first use of atomic weapons in war. Tens of thousands were killed in the initial explosions and many more would later succumb to radiation poisoning . On August 10, one day after the bombing of Nagasaki, the Japanese government issued a statement agreeing to accept the Allied surrender terms that had been dictated in the Potsdam Declaration .

The turning point in the quest for atomic energy came in January 1939, eight months before the start of World War II. German scientists Otto Hahn and Fritz Strassmann , following a clue provided by Irène Joliot-Curie and Pavle Savić in France (1938), proved definitely that the bombardment of uranium with neutrons produced radioisotopes of barium , lanthanum , and other elements from the middle of the periodic table .

The significance of this discovery was communicated by Lise Meitner and Otto Frisch , two Jewish scientists who had fled Germany, to Niels Bohr in Copenhagen. Bohr had been preparing to journey to the United States , and he arrived in New York on January 16, 1939. He discussed the matter with Albert Einstein , John Archibald Wheeler , and others before announcing to the world on January 26 the discovery of a process that Meitner and Frisch had termed fission . Enrico Fermi proposed to Bohr that neutrons might be released during the fission process, thus raising the possibility of a sustained nuclear chain reaction . These revolutionary suggestions triggered a flurry of activity in the world of physics. Subsequent studies by Bohr and Wheeler indicated that fission did not occur in uranium-238, the isotope of uranium most commonly found in nature, but that fission could take place in uranium-235 . Gradually many of the riddles surrounding fission were resolved, and by June 1940 the basic facts concerning the release of atomic energy were known throughout the scientific world.

The Manhattan Project

While engaged in one war in Europe and another in the Pacific , the United States would launch the largest scientific effort undertaken to that time. It would involve 37 installations throughout the country, more than a dozen university laboratories, and 100,000 people, including the Nobel Prize-winning physicists Arthur Holly Compton , Enrico Fermi, Richard Feynman , Ernest Lawrence , and Harold Urey .

The first contact between the scientific community and the U.S. government regarding atomic research was made by George B. Pegram of Columbia University . Pegram arranged a conference between Fermi and officers of the U.S. Navy in March 1939. In July Leo Szilard and Eugene Wigner conferred with Einstein, and the three later went to New York to meet with National Recovery Administration economist Alexander Sachs. Supported by a letter from Einstein, Sachs approached Pres. Franklin D. Roosevelt and explained the significance of nuclear fission to him. Roosevelt formed the Advisory Committee on Uranium, appointing Lyman Briggs, director of the National Bureau of Standards , to serve as its chair. In February 1940 a fund of $6,000 was made available to begin research; by the time of its completion, the project’s budget would exceed $2 billion.

U.S. officials were now well aware of Adolf Hitler ’s atomic ambitions. In his letter to Roosevelt, Einstein explicitly called attention to uranium reserves in Czechoslovakia that had fallen under the control of the Third Reich in March 1939. The British had also begun studying fission, and Urey and Pegram visited the United Kingdom to see what was being done there. By August 1943 a combined policy committee had been established with the United Kingdom and Canada . Later that year a number of scientists of those countries moved to the United States to join the project that by then was well underway.

On December 6, 1941, one day before the Japanese attack on Pearl Harbor , the project was placed under the direction of Vannevar Bush and the Office of Scientific Research and Development (OSRD). Bush’s staff included Harvard University Pres. James B. Conant , Pegram, Urey, and Lawrence, among others. Alongside this scientific body was created the “Top Policy Group,” consisting of Bush, Conant, Roosevelt, U.S. Vice Pres. Henry Wallace , U.S. Secretary of War Henry Stimson , and U.S. Army Chief of Staff George C. Marshall .

Because there was no way of knowing in advance what technique would succeed in creating a functional bomb, it was decided to work simultaneously on several methods of isolating uranium-235 while also researching reactor development. The goal was twofold: to learn more about the chain reaction for bomb design and to develop a method of producing a new element, plutonium , which was expected to be fissile and could be isolated from uranium chemically. Lawrence and his team developed an electromagnetic separation process at the University of California, Berkeley , while Urey’s group at Columbia University experimented with the conversion of uranium into a gaseous compound that was then permitted to diffuse through porous barriers. Both of these processes, particularly the diffusion method, required large complex facilities and huge amounts of electric power to produce even small amounts of separated uranium-235. It soon became clear that an enormous physical infrastructure would have to be built to support the project.

On June 18, 1942, the War Department assigned management of construction work related to the project to the U.S. Army Corps of Engineers ’ Manhattan District (much early atomic research—most notably Urey’s group—was based at Manhattan’s Columbia University). On September 17, 1942, Brig. Gen. Leslie R. Groves was placed in charge of all Army activities relating to the project. “Manhattan Project” became the code name applied to this body of atomic research that would extend across the country.

The first experimental reactor—a graphite cube about 8 feet (2.4 meters) on edge and containing about seven tons of uranium oxide—had been set up at Columbia University in July 1941. By the end of that year, reactor work had been transferred to the University of Chicago , where Arthur Holly Compton and his cryptically named “Metallurgical Laboratory” were considering related problems. On December 2, 1942, the first self-sustaining nuclear chain reaction was carried out under Fermi’s supervision in Chicago Pile No. 1, a reactor that Fermi had constructed in a squash court under the bleachers of Stagg Field, the university’s football stadium. It had now been proven that the controlled release of atomic energy was feasible for the production of power and the manufacture of plutonium.

In February 1943 construction began on a pilot uranium enrichment plant located on the Clinch River in the Tennessee Valley, about 15 miles (about 24 km) west of Knoxville , Tennessee. The Clinton Engineer Works (later known as Oak Ridge ) occupied a 70-square-mile (180-square-km) tract of land and came to employ roughly 5,000 technicians and maintenance personnel. For the project’s full-sized reactors, however, a more isolated site would be necessary. Groves had expressed concern about the pilot reactor’s proximity to Knoxville, and the larger reactors would have significantly greater power needs than could be accommodated in the Tennessee Valley.

In January 1943 Groves had selected a 580-square-mile (1,500-square-km) tract in south-central Washington for the project’s plutonium production facilities. The location was desirable for its relative isolation and for the availability, in large quantities, of cooling water from the Columbia River and electric power from the Grand Coulee Dam and Bonneville Dam hydroelectric installations . The creation of what came to be known as the Hanford Engineer Works required a significant displacement of the local population. Residents of the towns of Hanford, Richland , and White Bluffs were given just 90 days to vacate their homes, and the Wanapum Native American people were forced to relocate to Priest Rapids, losing access to their traditional fishing grounds on the Columbia. At its peak in the summer of 1944, the huge complex at Hanford employed more than 50,000 people.

For the final stages of the project, it was necessary to find a location that was even more remote than Hanford for the purposes of both security and safety. A site was chosen by the Manhattan Project’s scientific director, J. Robert Oppenheimer , on an isolated mesa at Los Alamos , New Mexico , 34 miles (55 km) north of Santa Fe . Beginning in April 1943, scientists and engineers began arriving at the Los Alamos Laboratory , as it was then called. Under Oppenheimer’s direction, this team was tasked with developing methods of reducing the fissionable products of the Clinton and Hanford production plants to pure metal and fabricating that metal into the components of a deliverable weapon. The weapon had to be small enough that it could be dropped from a plane and simple enough that it could be fused to detonate at the proper moment in the air above the target. Most of these issues had to be addressed before any significant stores of fissionable material had been produced, so that the first adequate amounts could be used in a functional bomb. At its peak in 1945 more than 5,000 scientists, engineers, technicians, and their families lived at the Los Alamos site.

Roosevelt died on April 12, 1945, and within 24 hours Pres. Harry S. Truman had been briefed about the atomic bomb program by Stimson. Germany surrendered in May 1945, thus ending the war in Europe, but combat raged on in the Pacific . Sanguinary battles at Iwo Jima (February–March 1945) and Okinawa (April–June 1945) offered a preview of what an invasion of the Japanese home islands might look like, and there remained a strong impetus to see the Manhattan Project through to its conclusion. By the summer of 1945, the production plants had delivered a sufficient amount of fissionable material to produce a nuclear explosion, and bomb development had advanced to a point that an actual field test of a nuclear weapon could be conducted. Such a test would obviously be no simple affair. A vast array of complex equipment had to be assembled so that the success or failure of the test could be analyzed.

The bomb development teams at Los Alamos had settled on two possible designs. One, fueled by uranium-235, would utilize a “gun assembly” that used high explosives to shoot two subcritical slugs of fissionable material together in a hollow tube. The violent collision of the two slugs would cause the uranium-235 to reach critical mass , thus triggering a chain reaction and explosion. Engineers were confident that this comparatively simple design would work, but a sufficient quantity of uranium-235 would not be available until about August 1, 1945. The Hanford site would be able to deliver enough plutonium-239 for testing by early July, but Los Alamos scientists had determined that the gun assembly model would not be compatible with plutonium as a fuel source. An alternative design had been proposed, one that would use concentric layers of high explosives to implode the fissionable material under enormous pressures into a denser mass that would immediately achieve criticality. It was believed that this “implosion” design would be the most efficient way to weaponize the meager amount of plutonium that had been produced thus far.

For the test, Oppenheimer selected a location on the Alamogordo Bombing Range (now White Sands Missile Range), 120 miles (193 km) south of Albuquerque , New Mexico. He called the site “Trinity” in reference to one of John Donne ’s Holy Sonnets . The first atomic bomb—a plutonium implosion device called “Gadget”—was raised to the top of a 100-foot (30-meter) steel tower that was designated “Zero.” The area at the base of the tower was marked as “Ground Zero,” a term that would pass into common parlance to describe the center of an (often catastrophic) event. Military officials and scientists occupied observation posts at distances ranging from 10,000 to 17,000 yards (9 to 15.5 km). They had been instructed to lie down with their feet toward the tower and to protect their eyes from the blinding flash of the explosion.

On the morning of the test, the skies were dark and it was raining, with occasional lightning. “Gadget” was detonated at 5:29:45 am on July 16, 1945. The explosion caused a flash that illuminated the mountain peaks 10 miles (16 km) away. Soon there followed a tremendous sustained roar accompanied by a tornado-like burst of wind. Where the tower had stood, there was a great surging ball of fire, followed by a mushroom cloud that rose some 40,000 feet (12,200 meters) into the sky. The heat of the explosion had completely vaporized the tower; in its place was a saucer-shaped crater about a half mile (800 meters) in diameter and 25 feet (almost 8 meters) deep. The floor of the crater was fused into a glassy jade-colored mineral subsequently dubbed trinitite. The bomb had generated an explosive power equivalent to approximately 21,000 tons of trinitrotoluene (TNT). The blast was visible from a distance of 50 miles (80 km), and it shattered windows 125 miles (200 km) away. Residents of Gallup , New Mexico, more than 180 miles (290 km) from Ground Zero, reported feeling the ground shake. In an attempt to head off questions about the world-changing event that had occurred at Trinity, the army issued a brief statement to the press: “A remotely located ammunition magazine containing a considerable amount of high explosives and pyrotechnics exploded, but there was no loss of life or limb to anyone.”

News of the successful test reached Truman, who was attending the final meeting of the “Big Three” Allied powers at Potsdam , Germany. Truman informed Soviet leader Joseph Stalin that the United States possessed “a new weapon of unusual destructive force.” On July 26 the Big Three issued an ultimatum , calling on Japan to surrender unconditionally or face “prompt and utter destruction.” When it became clear that no surrender was imminent , plans to use the bomb went into effect. Some within the Manhattan Project had argued for a demonstration explosion on an uninhabited site in the Pacific. This was considered but soon discarded, largely because of concerns that the demonstration bomb might not prompt sufficient reaction from the Japanese government. By this time, several dozen B-29 bombers had been modified to carry the weapons, and a staging base at Tinian , in the Mariana Islands , 1,500 miles (2,400 km) south of Japan, had been expanded into the largest airfield in the world.

On July 16, just hours after the successful completion of the Trinity test, the heavy cruiser USS Indianapolis left port at San Francisco with the gun assembly mechanism, roughly half of the U.S. supply of uranium-235, and several Los Alamos technicians. The remainder of the U.S. uranium-235 stockpile was flown to Tinian on transport planes. Upon the arrival of the Indianapolis at Tinian on July 26, assembly began on the bomb, dubbed Little Boy . The Indianapolis departed Tinian after the delivery, but it was sunk en route to the Philippines by the Japanese submarine I-58 on July 30. Hundreds of crew members who survived the torpedo attack died in the water while awaiting a rescue. The components of a second bomb, a plutonium device nicknamed Fat Man , were transported to Tinian by air. By August 2, 1945, both bombs had arrived at Tinian, and U.S. commanders were waiting only for a break in the weather to order the execution of Special Bombing Mission 13—an atomic attack on the Japanese home islands.

Groves had chaired the committee responsible for target selection, and by the end of May 1945 the list had been narrowed to Kokura , Hiroshima, Niigata , and Kyōto , all cities that had not yet been subjected to Gen. Curtis LeMay ’s strategic bombing campaign . Kyōto, Japan’s ancient capital, was consistently placed at the top of the list, but Stimson appealed directly to Truman to remove it from consideration because of its cultural importance. Nagasaki was added in its place. Hiroshima became the primary target because of its military value—the city served as the headquarters of the Japanese Second Army—and because planners believed that the compactness of the urban center would most vividly demonstrate the destructive power of the bomb.

The pilots, mechanics, and crews of the 509th Composite Group of the Twentieth Air Force had all trained with the specially modified B-29s that would serve as delivery vehicles for the bombs. Col. Paul W. Tibbets, Jr., the commander of the 509th, would pilot the B-29 that would drop the first bomb. His 11-man crew included Maj. Thomas Ferebee as bombardier and Manhattan Project ordnance expert Capt. William (“Deak”) Parsons as weaponeer. Tibbets personally selected plane number 82 for the mission, and, shortly before taking off at approximately 2:45 am on August 6, 1945, Tibbets asked a maintenance worker to paint his mother’s name— Enola Gay —on the nose of the aircraft. Two other B-29s accompanied the Enola Gay to serve as observation and camera planes. Once the Enola Gay was airborne, Parsons added the final components to Little Boy . This was done because a number of the modified B-29s had crashed on takeoff, and there was some concern that a crash would cause a fully assembled bomb to detonate, wiping out the installation at Tinian.

The skies were clear, and the Enola Gay encountered no opposition while approaching the target. At 7:15 am (Tinian time) Parsons armed the weapon, and the Enola Gay ascended to an attack altitude of 31,000 feet (9,450 meters). A trio of B-29s had flown ahead of the strike force to perform weather reconnaissance over the primary (Hiroshima) and secondary (Kokura and Nagasaki) targets. The pilot of the Hiroshima mission radioed Tibbets that there was little cloud cover and that he should proceed to the primary target. Just after 8:00 am local time (9:00 am Tinian time), the crew of the Enola Gay sighted Hiroshima. At around 8:12 am Tibbets relinquished control of the aircraft to Ferebee, who began his bombing run. Ferebee’s aim point was the Aioi Bridge, a distinctive T-shaped span over the Ōta River. Tibbets ordered his crew to don their protective goggles, and at 8:15 am the bomb was released. Tibbets immediately put the Enola Gay into a sharp turn that, he hoped, would carry it beyond the bomb’s blast radius.

It took roughly 45 seconds for Little Boy to descend to an altitude of 1,900 feet (580 meters), at which point it exploded in the sky directly above Shima Hospital. Within a fraction of a second of the detonation, the temperature at ground level exceeded 7,000 °C (12,600 °F) and a powerful blast wave scoured the landscape. Out of a population of 343,000 inhabitants, some 70,000 people were killed instantly, and by the end of the year the death toll had surpassed 100,000. Two-thirds of the city area was destroyed. “Nuclear shadows” were all that remained of people who had been subjected to the intense thermal radiation . A massive mushroom cloud rose to a height of more than 40,000 feet (more than 12 km). Although less than 2 percent of the uranium-235 contained in Little Boy had achieved fission, the bomb was horrifying in its destructive power. The explosive yield was the equivalent of 15,000 tons of TNT. Sgt. Bob Caron, the Enola Gay ’s tail gunner and the only member of the crew to directly observe the blast, described the scene as a “peep into hell.” A series of shockwaves rocked the Enola Gay as it departed the area, and at a distance of nearly 400 miles (640 km) the mushroom cloud was still visible. Upon returning to Tinian, after a flight of just over 12 hours, Tibbets was awarded the Distinguished Service Cross.

Later that day, Truman addressed the people of the United States:

Sixteen hours ago an American airplane dropped one bomb on Hiroshima, an important Japanese Army base. That bomb had more power than 20,000 tons of TNT. It had more than 2,000 times the blast power of the British “Grand Slam,” which is the largest bomb ever yet used in the history of warfare. The Japanese began the war from the air at Pearl Harbor . They have been repaid many fold. And the end is not yet. With this bomb we have now added a new and revolutionary increase in destruction to supplement the growing power of our armed forces. In their present form these bombs are now in production, and even more powerful forms are in development. It is an atomic bomb. It is a harnessing of the basic power of the universe. The force from which the sun draws its power has been loosed against those who brought war to the Far East.

Truman further noted, “We have spent two billion dollars on the greatest scientific gamble in history—and won.” Poet and author James Agee , writing in Time , offered something of a counterpoint to Truman’s speech:

The race had been won, the weapon had been used by those on whom civilization could best hope to depend; but the demonstration of power against living creatures instead of dead matter created a bottomless wound in the living conscience of the race. The rational mind had won the most Promethean of its conquests over nature, and had put into the hands of common man the fire and force of the sun itself.

News of Hiroshima’s destruction was only slowly understood, and some Japanese officials argued that their own stalled atomic program had demonstrated how difficult it would be to create such a weapon. It was possible, they argued, that the bomb dropped on Hiroshima was the only one in the American arsenal. Other members of the Japanese government had been arguing for months in favor of a negotiated settlement, perhaps mediated by the Soviets. That window was abruptly closed on August 8, 1945, two days after the Hiroshima bombing, when the Soviet Union declared war against Japan.

• History Classics
• Your Profile
• Find History on Facebook (Opens in a new window)
• Find History on Twitter (Opens in a new window)
• Find History on YouTube (Opens in a new window)
• Find History on Instagram (Opens in a new window)
• Find History on TikTok (Opens in a new window)
• This Day In History
• History Podcasts
• History Vault

Atomic Bomb History

By: History.com Editors

Updated: November 9, 2022 | Original: September 6, 2017

The atomic bomb and nuclear bombs are powerful weapons that use nuclear reactions as their source of explosive energy. Scientists first developed nuclear weapons technology during World War II. Atomic bombs have been used only twice in war—both times by the United States against Japan at the end of World War II, in Hiroshima and Nagasaki. A period of nuclear proliferation followed that war, and during the Cold War, the United States and the Soviet Union vied for supremacy in a global nuclear arms race.

Nuclear Bombs and Hydrogen Bombs

A discovery by nuclear physicists in a laboratory in Berlin, Germany, in 1938 made the first atomic bomb possible, after Otto Hahn, Lise Meitner and Fritz Strassman discovered nuclear fission.

In nuclear fission, the nucleus of an atom of radioactive material splits into two or more smaller nuclei, which causes a sudden, powerful release of energy. The discovery of nuclear fission opened up the possibility of nuclear technologies, including weapons.

Atomic bombs get their energy from fission reactions. Thermonuclear weapons, or hydrogen bombs, rely on a combination of nuclear fission and nuclear fusion. Nuclear fusion is another type of reaction in which two lighter atoms combine to release energy.

Manhattan Project

On December 28, 1942, President Franklin D. Roosevelt authorized the formation of the Manhattan Project to bring together various scientists and military officials working on nuclear research.

The Manhattan Project was the code name for the American-led effort to develop a functional atomic bomb during World War II . The project was started in response to fears that German scientists had been working on a weapon using nuclear technology since the 1930s.

Who Invented the Atomic Bomb?

Much of the work in the Manhattan Project was performed in Los Alamos, New Mexico , under the direction of theoretical physicist J. Robert Oppenheimer , the “ father of the atomic bomb .”

On July 16, 1945, in a remote desert location near Alamogordo, New Mexico , the first atomic bomb was successfully detonated—the Trinity Test . It created an enormous mushroom cloud some 40,000 feet high and ushered in the Atomic Age.

Watch Historic Footage of Atomic Test Explosions

This footage of two nuclear‑test explosions in Hawaii reveal a destructive power so massive it’s still hard to fathom. | Courtesy of the Department of Energy Nevada Operations Office

How Did Emperor Hirohito Respond to the Atomic Bomb Attacks?

After the devastating bombings at Hiroshima and Nagasaki, the leadership of Japanese Emperor Hirohito was put to the test.

Hiroshima And Nagasaki Bombings

Scientists at Los Alamos had developed two distinct types of atomic bombs by 1945—a uranium-based design called “the Little Boy” and a plutonium-based weapon called “the Fat Man.” (Uranium and plutonium are both radioactive elements.)

While the war in Europe had ended in April, fighting in the Pacific continued between Japanese forces and U.S. troops. In late July, President Harry Truman called for Japan’s surrender with the Potsdam Declaration . The declaration promised “prompt and utter destruction” if Japan did not surrender.

On August 6, 1945, the United States dropped its first atomic bomb from a B-29 bomber plane called the Enola Gay over the city of Hiroshima , Japan. The “Little Boy” exploded with about 13 kilotons of force, leveling five square miles of the city and killing 80,000 people instantly. Tens of thousands more would later die from radiation exposure.

When the Japanese did not immediately surrender, the United States dropped a second atomic bomb three days later on the city of Nagasaki . The “Fat Man” killed an estimated 40,000 people on impact.

Nagasaki had not been the primary target for the second bomb. American bombers initially had targeted the city of Kokura, where Japan had one of its largest munitions plants, but smoke from firebombing raids obscured the sky over Kokura. American planes then turned toward their secondary target, Nagasaki.

Citing the devastating power of “a new and most cruel bomb,” Japanese Emperor Hirohito announced his country’s surrender on August 15—a day that became known as ‘ V-J Day ’—ending World War II.

Museums Still Can’t Agree on How to Talk About the 1945 Atomic Bombing of Japan

The Los Alamos Historical Museum halted a Japanese exhibition on the bombings of Hiroshima and Nagasaki because of a controversy over its message of abolishing nuclear weapons.

“Father of the Atomic Bomb” Was Blacklisted for Opposing H‑Bomb

After leading development of the first atomic bomb, J. Robert Oppenheimer called for controls on nuclear weapons. It cost him his job.

Photos: Hiroshima and Nagasaki, Before and After the Bombs

Before the 1945 atomic blasts, they were thriving cities. In a flash, they became desolate wastelands.

The Cold War

The United States was the only country with nuclear weaponry in the years immediately following World War II. The Soviet Union initially lacked the knowledge and raw materials to build nuclear warheads.

Within just a few years, however, the U.S.S.R. had obtained—through a network of spies engaging in international espionage—blueprints of a fission-style bomb and discovered regional sources of uranium in Eastern Europe. On August 29, 1949, the Soviets tested their first nuclear bomb.

The United States responded by launching a program in 1950 to develop more advanced thermonuclear weapons. The Cold War arms race had begun, and nuclear testing and research became high-profile goals for several countries, especially the United States and the Soviet Union.

Cuban Missile Crisis

Over the next few decades, each world superpower would stockpile tens of thousands of nuclear warheads. Other countries, including Great Britain, France, and China, developed nuclear weapons during this time, too.

To many observers, the world appeared on the brink of nuclear war in October of 1962. The Soviet Union had installed nuclear-armed missiles on Cuba, just 90 miles from U.S. shores. This resulted in a 13-day military and political standoff known as the Cuban Missile Crisis .

President John F. Kennedy enacted a naval blockade around Cuba and made it clear the United States was prepared to use military force if necessary to neutralize the perceived threat.

Disaster was avoided when the United States agreed to an offer made by Soviet leader Nikita Khrushchev to remove the Cuban missiles in exchange for the United States promising not to invade Cuba.

Three Mile Island

Many Americans became concerned about the health and environmental effects of nuclear fallout—the radiation left in the environment after a nuclear blast—in the wake of World War II and after extensive nuclear weapons testing in the Pacific during the 1940s and 1950s.

The antinuclear movement emerged as a social movement in 1961 at the height of the Cold War. During Women Strike for Peace demonstrations on November 1, 1961 co-organized by activist Bella Abzug , roughly 50,000 women marched in 60 cities in the United States to demonstrate against nuclear weapons.

The antinuclear movement captured national attention again in the 1970s and 1980s with high profile protests against nuclear reactors after the Three Mile Island accident—a nuclear meltdown at a Pennsylvania power plant in 1979.

In 1982, a million people marched in New York City protesting nuclear weapons and urging an end to the Cold War nuclear arms race. It was one of the largest political protests in United States history.

Nuclear Non-Proliferation Treaty (NPT)

The United States and Soviet Union took the lead in negotiating an international agreement to halt the further spread of nuclear weapons in 1968.

The Treaty on the Non-Proliferation of Nuclear Weapons (also called the Non-Proliferation Treaty or NPT) went into effect in 1970. It separated the world’s countries into two groups—nuclear weapons states and non-nuclear weapons states.

Nuclear weapons states included the five countries that were known to possess nuclear weapons at the time—the United States, the U.S.S.R., Great Britain, France and China.

According to the treaty, nuclear weapons states agreed not to use nuclear weapons or help non-nuclear states acquire nuclear weapons. They also agreed to gradually reduce their stockpiles of nuclear weapons with the eventual goal of total disarmament. Non-nuclear weapons states agreed not to acquire or develop nuclear weapons.

When the Soviet Union collapsed in the early 1990s, there were still thousands of nuclear weapons scattered across Eastern Europe and Central Asia. Many of the weapons were located in Belarus, Kazakhstan and Ukraine. These weapons were deactivated and returned to Russia.

Illegal Nuclear Weapon States

Some countries wanted the option of developing their own nuclear weapons arsenal and never signed the NPT. India was the first country outside of the NPT to test a nuclear weapon in 1974.

Other non-signatories to the NTP include: Pakistan, Israel and South Sudan. Pakistan has a known nuclear weapons program. Israel is widely believed to possess nuclear weapons, though has never officially confirmed or denied the existence of a nuclear weapons program. South Sudan is not known or believed to possess nuclear weapons.

North Korea

North Korea initially signed the NPT treaty, but announced its withdrawal from the agreement in 2003. Since 2006, North Korea has openly tested nuclear weapons, drawing sanctions from various nations and international bodies.

North Korea tested two long-range intercontinental ballistic missiles in 2017—one reportedly capable of reaching the United States mainland. In September 2017, North Korea claimed it had tested a hydrogen bomb that could fit on top an intercontinental ballistic missile.

Iran, while a signatory of the NPT, has said it has the capability to initiate production of nuclear weapons at short notice.

Pioneering Nuclear Science: The Discovery of Nuclear Fission. International Atomic Energy Agency . The Development and Proliferation of Nuclear Weapons. NobelPrize.org . Here are the facts about North Korea’s nuclear test. NPR .

Sign up for Inside History

Get HISTORY’s most fascinating stories delivered to your inbox three times a week.

By submitting your information, you agree to receive emails from HISTORY and A+E Networks. You can opt out at any time. You must be 16 years or older and a resident of the United States.

More details : Privacy Notice | Terms of Use | Contact Us

National Archives News

The Atomic Bombing of Hiroshima and Nagasaki, August 1945

Photograph of Hiroshima after the atomic bomb. (National Archives Identifier 22345671 )

The United States bombings of the Japanese cities of Hiroshima and Nagasaki on August 6 and August 9, 1945, were the first instances of atomic bombs used against humans, killing tens of thousands of people, obliterating the cities, and contributing to the end of World War II. The National Archives maintains the documents that trace the evolution of the project to develop the bombs, their use in 1945, and the aftermath.

Online Exhibits

The Atomic Bombing of Hiroshima and Nagasaki   features a letter written by Luis Alvarez, a physicist who worked on the Manhattan Project, on August 6, 1945, after the first atomic bomb was dropped on Hiroshima, Japan.

[Photograph: The atomic cloud rising over Nagasaki, Japan, August 9, 1945. National Archives Identifier 535795 ]

A People at War looks at the 509 Composite Group, the unit selected to carry the atomic bomb to Hiroshima.

[Photograph: Col. Paul Tibbets, Jr., waves from the cockpit of the Enola Gay before departing for Hiroshima, August 6, 1945. National Archives Identifier  535737 ]

Photograph Gallery

"Little Boy" atomic bomb being raised into plane on Tinian Island before the flight to Hiroshima. National Archives Identifier  76048583

Hiroshima after the atomic bomb. National Archives Identifier  22345671

Hiroshima after the atomic bomb. National Archives Identifier  22345679

Hiroshima after the atomic bomb. National Archives Identifier  22345680

Hiroshima after the atomic bomb. National Archives Identifier  148728174

Nuclear weapon of the "Fat Man" type, the kind detonated over Nagasaki, Japan. National Archives Identifier  175539928

The atomic cloud rising over Nagasaki, Japan. National Archives Identifier  535795

Nagasaki after the atomic bomb. National Archives Identifier  39147824

Nagasaki after the atomic bomb. National Archives Identifier  39147850

Additional Photographs

Atomic Bomb Preparations at Tinian Island, 1945

Photographs used in the report Effects of the Atomic Bomb on Hiroshima, Japan

Manhattan Project Notebook

Atomic bomb/Enola Gay preparations for the bombing missions

Post-bombing aerial and on-the-ground images of Hiroshima

Empty bottle of Chianti Bertolli wine signed by scientists who worked on the Manhattan Project

Archival Film

Hiroshima and Nagasaki Effects, 1945

The Last Bomb ,  a 1945 film, done in Technicolor, by the Army Air Forces Combat Camera Units and Motion Picture Units covering the B-29 bombing raids on Japan

Effects on the human body of radiation from the atomic bomb

Additional Records

Photos: Atomic Bomb Preparations at Tinian Island, 1945

Atomic bomb/ Enola Gay preparations for the bombing missions

Post-Hiroshima bombing aerial and on-the-ground images

Color image of Hiroshima after bombing

Manhattan Project records from Oak Ridge, TN

Blogs and Social Media Posts

Unwritten Record:  Atomic Bombings of Hiroshima and Nagasaki

Unwritten Record:  Witness to Destruction: Photographs and Sound Recordings Documenting the Hiroshima Bombing

Forward with Roosevelt:  Found in the Archives: The Einstein Letter

Pieces of History:  Little Boy: The First Atomic Bomb

Pieces of History:  Harry Truman and the Bomb

Pieces of History:  Morgantown Ordnance Works (part of the Manhattan Project) Panoramas, 1940–1942

Today's Document:  Petition from Manhattan Project Scientists to President Truman

For Educators

Docs Teach resources on the atomic bomb

Teaching with Documents:  Photographs and Pamphlet about Nuclear Fallout

Kennedy Library: “The Presidency in the Nuclear Age”

At the Presidential Libraries

Roosevelt Library: Albert Einstein’s letter to FDR regarding the atomic bomb

Truman Library: “The Decision to Drop the Atomic Bomb ”

Truman Library: Additional records on the bombing of Hiroshima

Truman Library:  President Truman's Diary Entry for July 17, 1945 (the day before Truman learned that the United States had successfully tested the world's first atomic bomb)

Truman Library: Memo for the Record, Manhattan Project, July 20, 1945

Truman Library: Petition from Leo Szilard and other scientists to President Truman

Eisenhower Library: Atoms for Peace

Kennedy Library: “ The Presidency in the Nuclear Age: The Race to Build the Bomb and the Decision to Use It”

The Man Who Wrote A Paper On How To Build A Nuclear Bomb That Was So Good, It Was Seized By The FBI

In 1976, an underachieving Princeton student named John Aristotle Philips wrote a term paper describing how to build a nuclear bomb. He received an “A” but never got his paper back as it was seized by the FBI.

Here’s the story of the “A-Bomb Kid”.

In 1976, John Aristotle Phillips was the mascot in the Tiger outfit at Princeton University. He was not the brightest student of his class and his academic prospects were not so promising. “If I flunk another course,” he admitted, “I’ll be bounced out of the Big U right on my ass”. (the article continues after the ad)

So Phillips decided to change all that. He proposed to write a paper that would “end all term papers”. Its subject? “How to Build Your Own Atomic Bomb”. After getting approved by his instructor Freeman Dyson, Phillips started his research. His main source of information was the National Technical Information Service were he studied all the available declassified documents.

And he made it. After numerous calculations, Phillips created a paper in which he described how anyone could build its own atomic bomb!

But how good was it?

According to his teacher, it was extremely well written. Dyson told Phillips that he would give him an “A” but, as soon as the grade was registered, the paper had to be burned. Phillips agreed but he didn’t have to. He never got the paper back. The term paper ended up in FBI which seized and classified it. In the following months the Pakistani embassy tried to get a copy but it was too late.

If you like what you read, then you will definitely love this one:  US Army Was Developing A “Gay Bomb”, A Bomb That Would Make Enemy Troops Feel Attracted To Each Other

Photo: Saïd Business School, University of Oxford / YouTube, AETHERFORCE Photoshop: I’m A Useless Info Junkie Widget not in any sidebars

QUIZ: Test Your Knowledge With The Ultimate Science Quiz

VIDEO: The World’s Smallest, Fully Functioning Gun Fits In The Palm Of Your Hand

Copyright © I'm A Useless Info Junkie.

Ad Blocker Detected!

Privacy overview.

The A-Bomb Kid

Ben gillman may 30, 2019, submitted as coursework for ph241 , stanford university, winter 2019, introduction.

After World War 2, the U.S. government recognized the need for tight control over nuclear energy. [1] There was a movement to expand the knowledge about nuclear energy and use it for commercial purposes, but in order for this to happen the materials for and knowledge about bomb making needed to be tightly controlled. In 1946 President Truman signed the Atomic Energy Act, as seen in Fig. 1, to begin this process and establish the Atomic Energy Commission. [1] The act was revised in 1954 to further advance the commercial nuclear energy industry, and more tightly control civilian access to nuclear materials and information. [1]

John Aristotle Phillips was an undergraduate physics student at Princeton University in 1976. [2] He grew up in North Haven, Connecticut, spent two years at the University of California, Berkeley, and then transferred to Princeton. For a term paper in a class during his junior year, Phillips sought to show that nuclear weapons could fall into enemy hands much more easily than people thought. Using just nuclear engineering textbooks and 2 publicly available government documents, Phillips was able to design a nuclear bomb as a part of his paper, and therefore show that any terrorist group or energy nation would be able build a nuclear bomb without classified information. [2] Phillips's bomb design was assessed by nuclear physicist Frank Chilton as very likely to work, and Phillips was quoted as saying, "Its very simple. Any undergraduate physics major could have done what I did." [2]

John Aristotle Phillips gained a lot of attention for his term paper that showed making a nuclear bomb wasn't as difficult to learn as previously thought. He attracted new scrutiny to the difficulty of controlling nuclear information, even information that isn't ill-gotten. As the government today has to deal with the control of secret technology besides nuclear weapons, maybe they should look to the born secret doctrine as a way to combat the spread of information about chemical weapons, gene editing diseases, or cyber attacks.

© Ben Gillman. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.

[1] R. Gaertner " The Atomic Energy Act ," Physics 241, Stanford University, Winter 2016.

[2] R. Rein " A Princeton Tiger Designs An Atomic Bomb in a Physics Class ," People Magazine, 25 Oct 76.

[3] H. Morland "Born Secret ," Cardozo Law Review 26 , No. 4, 1401 (2005).

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• v.43(6); 2014 Oct

Nuclear Weapons Tests and Environmental Consequences: A Global Perspective

Remus prăvălie.

Faculty of Geography, Bucharest University, 1, Nicolae Bălcescu str., Bucharest, Romania

The beginning of the atomic age marked the outset of nuclear weapons testing, which is responsible for the radioactive contamination of a large number of sites worldwide. The paper aims to analyze nuclear weapons tests conducted in the second half of the twentieth century, highlighting the impact of radioactive pollution on the atmospheric, aquatic, and underground environments. Special attention was given to the concentration of main radioactive isotopes which were released, such as 14 C, 137 Cs, and 90 Sr, generally stored in the atmosphere and marine environment. In addition, an attempt was made to trace the spatial delimitation of the most heavily contaminated sites worldwide, and to note the human exposure which has caused a significantly increased incidence of thyroidal cancer locally and regionally. The United States is one of the important examples of assessing the correlation between the increase in the thyroid cancer incidence rate and the continental-scale radioactive contamination with 131 I, a radioactive isotope which was released in large amounts during the nuclear tests carried out in the main test site, Nevada.

Introduction

The end of World War II marked the beginning of the atomic age, when a number of states launched the nuclear arms race. Initially, in the synergistic context of Cold War geopolitics and the lack of effective international disarmament policies, countries like the United States, the USSR, the United Kingdom, France, and China became nuclear powers during 1945–1964 (Katz 2008 ; Schenck and Youmans 2012 ). During this period, a large number of nuclear tests were conducted in all global environments (atmosphere, underground, and underwater).

Between 1945 and 1963, the United States and the USSR conducted a large number of nuclear tests in the atmosphere, the most representative examples being the first nuclear explosions of the hydrogen bomb conducted in 1954 by the United States, in the Marshall Islands, on the Bikini atoll (the Castle Bravo test); and in 1961, by the USSR, in the Novaia Zemlia archipelago, north of the Ural mountains (the Tsar test) (Goodby 2005 ). The severe environmental damage caused by these nuclear tests, the most powerful ever to be conducted in the atmosphere, as well as the general context of global nuclear weapons tests, have created the premises of the first instance of large-scale international cooperation to eliminate nuclear weapons testing.

Thus, 1963 marked a milestone with the entry into force of the Limited Test Ban Treaty (LTBT), a treaty stipulating a ban on nuclear weapons tests in all global environments, except for the underground (Rubinson 2011 ). Although it was not signed by two key states—France and China (Mastny 2008 ), as these countries continued their nuclear weapons tests in the atmosphere—the treaty had a genuine impact in limiting radioactive isotopes in the atmosphere in the two hemispheres from 1963 on (Levin et al. 1994 ; Manning and Melhuish 1994 ).

The entry into force of the Non-Proliferation Treaty (NPT) in 1968, banning nuclear arming of all states of the world, with the exception of the five existing nuclear powers, was another key moment in the efforts to end the nuclear arms race and, indirectly, nuclear weapons testing (van der Meer 2011 ). Although the provisions of the treaty were to be implemented with the help of the International Atomic Energy Agency (IAEA) (Weitz 2011 ), geopolitical experiences of the last four decades have shown that, outside the scope of the NPT, a different category of nuclear states had emerged, including India, South Africa, Pakistan, North Korea, and apparently Israel (unconfirmed nuclear status) (McDonnell 2013 ), with some of these countries conducting nuclear weapons tests of their own.

In 1996, a new phase in stopping all types of nuclear tests began, with the United Nations adoption of the Comprehensive Nuclear-Test-Ban Treaty (CTBT 1996 ). However, the large number of nuclear weapons tests carried out in the atmosphere and underground during 1945–2013 (the last nuclear test was performed by North Korea) was responsible for the current environmental contamination with radioactive waste which resulted in ecologically and socially destroyed sites, due to high levels of radioactivity.

The present study is based on an analysis of the environmental impacts generated by nuclear weapons tests, mainly discussing the matter of atmospheric and oceanic environmental contamination both in global and regional contexts, and punctual matters concerning human exposure to radioactive pollution.

Geopolitical Context and Particularities of Nuclear Weapons Tests

The alarming nuclear arms race that the five nuclear powers launched in the second half of the twentieth century was the result of the special status they enjoyed during the international nuclear disarmament policies, of which the most representative example is the NPT (Grotto 2010 ; Prăvălie 2012 ).

These countries are part of the nuclear weapon states category, allowed to own nuclear weapons, as stipulated by the NPT from 1968 (Sauer 2006 ). The second category, the nuclear-armed states, is represented by India, South Africa, Pakistan, North Korea, and most likely Israel—the nuclear states armed between 1968 and 2006—currently considered outside the NPT (McDonnell 2013 ). The exception is South Africa, the country that disarmed itself after the year 1990 in the context of internal political changes (Magnarella 2008 ). The reasons which led to the proliferation of nuclear weapons are mainly of geopolitical nature: international prestige, geostrategic regional consolidation, and regional/global power status (van der Meer 2011 ). Therefore, testing nuclear weapons was one of the main ways of asserting nuclear power status, as well as the place held by these states in the hierarchy of nuclear geopolitics.

According to the data provided by the Stockholm International Peace Research Institute platform, 2053 nuclear tests were conducted worldwide during 1945–2006 (Fedchenko and Hellgren 2007 ). The majority (85 %) were conducted by the USA and the USSR during 1945–1992, while 14.5 % (300 tests) were conducted by the United Kingdom, France, and China (Fig.  1 a, b), and less than 1 % by India, Pakistan, and North Korea.

Temporal fluctuation in the number of nuclear tests carried out by the five nuclear powers ( a , b ), during 1945–1996 (data processing from Fedchenko and Hellgren 2007 ); the number of nuclear tests carried out in the global environments ( c ); and temporal fluctuation of nuclear tests conducted in the atmosphere ( d ) by the five nuclear powers during 1945–1980 (data processing from Fedchenko and Hellgren 2007 ); annual fission and fusion yields of nuclear tests (atmospheric and underground) produced by the five nuclear powers ( e ) during 1951–1992 (data processing after UNSCEAR 2000a )

Nuclear tests were conducted in all environments, namely in the atmosphere, underground, and underwater. Approximately 25 % (530 tests) were conducted in the atmosphere (or in a few cases under water) and 75 % in the underground (1517 tests), which are performed in almost 100 % of cases by the nuclear weapon states, and only in 0.3 % of cases by India, Pakistan, and North Korea/DPRK (Fig.  1 c). The USA and the USSR/Russia were responsible for 82 % of all the tests conducted in the atmosphere during 1945–1963 (Fig.  1 d) and for 86 % of those performed in the underground during 1951–1992.

In terms of energy released in nuclear explosions, expressed in megatonnes (Mt) of TNT equivalent, two different processes were involved, namely fission (of 235 U and 239 Pu isotopes in a chain reaction) and fusion (of the hydrogen isotopes, deuterium and tritium, in a thermonuclear process) (United Nations Scientific Committee on the Effects of Atomic Radiation, UNSCEAR 1993 ). In terms of radioactivity, the fission process produces a whole range of radionuclides, while the fusion process generally only produces tritium ( 3 H). However, the fusion process can also generate other radioactive materials (responsible for large amounts of radioactive debris), especially because of the inherent fission process of certain stages of thermonuclear reactions.

Between 1951 and 1992, nuclear tests totaled an explosive yield of approx. 530 Mt, of which 83 % (440 Mt) were due to the atmospheric nuclear tests carried out between 1951 and 1980, and 17 % (90 Mt) to the underground nuclear tests carried out between 1962 and 1992 (Fig.  1 e). Of the 440 Mt resulting from atmospheric tests, 57 % (251 Mt) were due to the fusion yield and 43 % (189 Mt) to the fission yield (UNSCEAR 2000a ). With regard to the five major nuclear powers, the Soviet Union is responsible for the production of 285 Mt (54 % of the total of 530 Mt), followed by the United States (200 Mt), China (22 Mt), France (13 Mt), and the United Kingdom (10 Mt) (UNSCEAR 2000a ).

Radioactive Pollution of the Atmosphere and Marine Environment

Approximately 90 % of all nuclear tests were conducted in the northern hemisphere, especially by the USA, the USSR/Russia, and China, and only 10 % (about 208 tests) in the southern hemisphere, by countries such as France and the United Kingdom. The northern hemisphere is therefore more contaminated than the southern one due to the presence of large quantities of radioactive isotopes (especially 14 C, 137 Cs, and 90 Sr) released into the atmosphere during nuclear weapons tests (UNSCEAR 1993 ). It is important to note that higher radioactivity of the northern hemisphere is also due to other factors, such as nuclear power-plant accidents. The most representative examples are the accidents at Chernobyl (1986) and Fukushima Daiichi (2011) (Grandin et al. 2011 ; Högberg 2013 ), which resulted in the release of large amounts of radionuclides into the atmosphere, of which the most important are 137 Cs and 131 I (UNSCEAR 1988 ; IAEA 2012 ).

Atmospheric nuclear weapons testing involved the release of considerable amounts of radioactive materials directly into the environment and caused the largest collective dose from man-made sources of radiation (UNSCEAR 2000a ). Among the most relevant studies on the total collective dose to the world population, the UNSCEAR reports stand out, especially those drawn up in 1982 (UNSCEAR 1982 ) and 1993 (UNSCEAR 1993 ), which are considered to be complete and valid even to this day (UNSCEAR 2000a ).

According to the UNSCEAR report ( 1993 ), following atmospheric nuclear testing, the main contributor to the total effective dose commitment to the world’s population is 14 C, contribution of which is 70 % (Fig.  2 ) over the course of thousands of years (out of the total dose of 3700 μSv, radionuclide 14 C accounts for 2580 μSv). Considerable percentages are also found in the cases of radionuclides, 137 Cs (13 %) and 90 Sr (3 %), as well as seven other radionuclides with effective dose percentage values ranging from 1.1 to 2.4 %. It is estimated that, apart from radionuclide 14 C, most of the other radionuclides will have delivered almost their entire dose over the next two centuries (UNSCEAR 1993 ).

Radionuclide contributions to the total effective dose equivalent commitment (%) to the world population from atmospheric nuclear testing (data processing after UNSCEAR 1993 )

Thus, when considering only 10 % of the 14 C dose commitment, which corresponds to the truncated effective dose commitment in the year 2200 (by which time most of the other radionuclides will have delivered almost their entire dose), the 14 C only contributes 19 % of the truncated effective dose commitment to the world’s population (Fig.  2 ). In this case, 137 Cs has the highest contribution to the truncated effective dose commitment (35 %), followed by radionuclide 90 Sr (8.1 %) (Fig.  2 ). This comparative situation is necessary because the 14 C radionuclide has a much greater half-life compared with most other radionuclides (it is estimated that approx. 70 % of the collective effective dose commitment will have been delivered in 10 000 years, for a projected future stabilized world population of 10 10 people) (UNSCEAR 2000b ).

The radionuclide 14 C is created by nitrogen ( 14 N)—naturally present in the atmosphere—capturing the neutrons released in excess during nuclear tests. Once formed, it is rapidly oxidized to 14 CO and then to 14 CO 2 , and it is then transferred to the global carbon reservoirs (the atmosphere, the ocean, and the terrestrial biosphere), where it is very difficult to remove from, because of its extremely long half-life (5730 years) (Currie et al. 2011 ).

In terms of the temporal evolution of mean annual 14 C concentration in the atmosphere, specialized measurements (Levin et al. 1994 ; Manning and Melhuish 1994 ) have shown that the values peaked in 1964, immediately after the entry into force of the LTBT (Fig.  3 a). This situation is valid especially in the northern hemisphere (according to the measurements taken at Vermunt Station, Austria), because in the case of the southern hemisphere, there is a gap of at least 1 year as far as the maximal recorded values are concerned (Wellington Station, New Zealand). The differences between the two stations, representative for the two hemispheres, can be explained by the time required by the isotope 14 C to propagate from the northern hemisphere to the southern hemisphere (Czeplak and Junge 1974 ). Therefore, in the case of the northern hemisphere, a peak concentration of 835 ‰ can be noticed in 1964, which then dropped steadily to a value of 226 ‰ by 1983 (Fig.  3 a). The southern hemisphere values recorded a peak of 642 ‰ in 1965 and a steady decline until 1993, the year for which the latest data are available (133 ‰) (Fig.  3 a). For these comparative situations, radiocarbon values are expressed in delta notation, which is the part per thousand deviation of the 14 C activity in the nineteenth century wood, according to the methodology developed by Stuiver and Polach ( 1977 ).

Fluctuations of mean annual concentration values of 14 C in the atmosphere in the northern hemisphere (Vermunt Station, Austria), during 1959–1983, and in the southern hemisphere (Wellington Station, New Zealand), during 1954–1993, in correlation with the temporal dynamics of total atmospheric nuclear tests ( a ) (data processing from Levin et al. 1994 and Manning and Melhuish 1994 ); the fluctuation of mean annual values of the 14 C concentrations on the ocean surface (0–75 m depth, North Atlantic), during 1950–1995, compared with annual mean values of the 14 C concentrations in the atmosphere from the northern hemisphere ( b ) (Vermunt Station, Austria) (data processing from Scourse et al. 2012 )

Therefore, the thermonuclear tests conducted during 1950–1960 almost doubled the concentration of isotope 14 C in the atmosphere, as a result of excessive injection of radioactive material into the stratosphere (Goodsite et al. 2001 ). Thus, the premises were created for an accelerated transfer of that isotope to the geospheres (atmosphere–ocean–biosphere), which resulted in the drop of 14 C concentrations in the atmosphere, starting from 1964 through to the present time (Krakauer et al. 2006 ).

The transfer of the radionuclide 14 C to the marine environment was possible through the exchange of gases in the ocean–atmosphere interference space. One of the methods used in reconstructing its fluctuations in the ocean consists in measuring its concentration in aquatic organisms, reservoirs that store 14 C. One example is the Arctica islandica bivalves mollusk, which served in the reconstruction of fluctuations of the radionuclide 14 C in the marine environment in the temperate zone of the North Atlantic (Scourse et al. 2012 ).

Following detailed investigations, it was found that over the last five decades, there has been a continuous transfer of the radionuclide 14 C from the atmosphere into the ocean (as far as the North Atlantic is concerned), but there are differences in terms of its assimilation by the marine environment. This means that an amplitude fluctuation of maximum–minimum values exists, which was significantly attenuated and also much delayed compared with the concentration values in the atmosphere (peaks during 1964–1965 followed by a constant decline up to the present time, compared with the values from the marine environment, peaking in 1974 followed by a steady decline up to the year of the latest available data, i.e., 1996) (Fig.  3 b). This situation is primarily due to the much larger marine carbon-storage reservoirs, compared with the atmospheric-storage reservoirs, as well as with regional hydrographical and biogeochemical features (Scourse et al. 2012 ).

Although the terrestrial biosphere has played an important role in the assimilation of the radionuclide 14 C from the atmosphere through the process of photosynthesis, the ocean was the largest storage reservoir of this radionuclide (Levin et al. 2010 ). Therefore, in terms of environmental effects, the marine environment has played an essential role in limiting these effects by means of its great assimilation capacity, although there are also some negative aspects concerning the radionuclide accumulation in the aquatic organisms. Otherwise, there would have been a major risk that the radionuclide 14 C be assimilated in enormous quantities in the biosphere (especially by forest ecosystems), and subsequently assimilated in the food chain, too (including in the human body).

Another radionuclide of paramount importance in residual global contamination from atmospheric nuclear testing is 137 Cs, with a 30-year half-life. It was released in large quantities during atmospheric testing, and continues to be a major source of anthropogenic radioactivity. As more than 70 % of the Earth’s surface is water-covered, the largest amounts of 137 Cs radioactive debris are accumulated in oceans and seas. At present, it is estimated that radionuclide 137 Cs is the main source of anthropogenic marine radioactivity, along with other important radionuclides (mainly 90 Sr, 239–240 Pu, 241 Am, 3 H, and 14 C), released in large quantities during nuclear tests (IAEA 1995 ). At the same time, at a planetary scale, global and local fallout events account for 90 % of the total 137 Cs isotope radioactivity, the remaining 10 % being linked to reprocessing plants (7 %) and the Chernobyl accident (3 %) (Aarkrog 2003 ).

Although global fallout is considered to be the main source of 137 Cs radioactivity in the marine environment (in 2000, most marine regions had 137 Cs radionuclide concentrations ranging from 1 to 10 Bq/m 3 ), it is noteworthy that the highest mean 137 Cs seawater concentration values were recorded in the Northeastern Atlantic Ocean (the Irish and North Seas), Barents Sea, Baltic Sea, and Black Sea (mean concentrations exceeded the 10 Bq/m 3 threshold in 2000), these marine regions’ radioactivity also resulting from the converging outcomes of additional sources (Livingston and Provinec 2000 ). The highest average concentration of 137 Cs worldwide was found in the Baltic Sea, namely about 100 Bq/m 3 . Although in these instances, nuclear tests had a significant radioactivity contribution (markedly in the Barents Sea, where the high 137 Cs concentrations are due to the radioactive debris resulting from the Novaya Zemlya test site’s activity), the main radioactivity sources are the Sellafield and La Hague reprocessing plants for the Northeastern Atlantic, and the Chernobyl accident for the Baltic Sea and the Black Sea (IAEA 1995 ). However, decreases in 137 Cs concentrations have been noticed lately in numerous marine regions worldwide. For instance, in the Barents Sea, surface water mean concentrations declined from a peak of almost 40 Bq/m 3 in 1979 to about 10 Bq/m 3 in 2000 (IAEA 2000 ; Livingston and Provinec 2000 ). This change can be attributed not only to significant decreases in local fallout but also to the diminishment in 137 Cs discharge from the Sellafield reprocessing plant.

An important aspect of this radionuclide is related to marine biota accumulation and the subsequent transfer to human body through food chain cycles. However, considering this type of transfer exclusively, the radiological impact on the global population is negligible, because, in 2000, the average annual effective dose was 3 μSv (for a hypothetical group living in the Northeastern Atlantic coast region with an average consumption of 100 kg of fish and 10 kg of shellfish per year), which is considerably lower than the accepted value for the public of 1 mSv (Livingston and Provinec 2000 ).

90 Sr (28.8-year half-life) is a particularly noteworthy radionuclide as well, released in large quantities in the terrestrial and marine environments during atmospheric nuclear tests. It was found that 90 % of the total deposition of 90 Sr and 137 Cs occurs as wet deposition during rainfall (UNSCEAR 2000b ). In this respect, there are common traits with nuclear accidents like the one at Chernobyl, which involved the atmosphere-to-ground level transfer of radionuclide 90 Sr at a rate of about 96 % as wet deposition (WHO 2010 ). As in the case of radionuclide, 137 Cs, two of the most important environmental consequences of this radionuclide’s transfer in the terrestrial environment are the soil deposition and soil-to-plant transfer, which were conditioned during nuclear testing from one region to another by climatic factors, soil physicochemical properties, and plant genetic peculiarities (Zhu and Shaw 2000 ). Subsequently, the transfer to the human body through food chain cycles was the main threat to the local population’s health (UNSCEAR 1993 , 2000b ).

With regard to the marine environment, an important feature of sea and ocean transfers is the river runoff transport mechanism (of water and sediments), which seems to have been acutely velocious in numerous regions of the world (particularly in the Pacific region, where river discharges are distinctly high), compared with other radionuclides (Hamilton et al. 1996 ). However, given the synergic context of global and local fallouts, and of reprocessing plant discharges, the North Atlantic is, in this instance as well, among the most heavily contaminated marine regions in the world. Nonetheless, over the recent decades, the radioactivity level decreased in most regions, even in the ones with the greatest exposure to nuclear-testing effects. For instance, in the Kara Sea, where the highest concentrations of 90 Sr in surface water associated with local fallout (Novaya Zemlya) were reached in 1963 (approx. 39 Bq/m 3 ), concentration values decreased significantly over the recent decades (approx. 5 Bq/m 3 in 1994) (IAEA 2000 ).

Spatial Variability of Nuclear Tests in the Global Context. Critical Issues of Contamination

According to the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), the United States has conducted the largest number of nuclear weapons tests, most of them conducted especially on the North American soil (Fig.  4 ). The Nevada desert is the major region where 44 % of all the nuclear tests worldwide were conducted. The environmental consequences are related to atmospheric contamination with radioactive isotopes (especially 14 C and 137 Cs) following the atmospheric nuclear tests conducted during 1951–1963. Other negative effects reported were related to atmospheric contamination with the radionuclides, 131 I and 133 I, which were later transferred to the biosphere mainly through rainfalls (Simon et al. 2006 ). The radionuclide 131 I was one of the main causes of increase thyroid cancer occurrence in the United States, as it was released in large quantities mainly during atmospheric nuclear tests (especially during 1951–1958) (Hundahl 1998 ; Gilbert et al. 1998 , 2010 ).

The spatial distribution, type, the number, and the period/year of nuclear tests conducted by the United States during 1945–1992 (data processing from http://www.ctbto.org/map/ ); and spatial data modeling after digital elevation model, ETOPO1 (data processing from http://www.ngdc.noaa.gov/mgg/global/global.html )

Currently, in the Nevada Test Site region, there is a high risk of groundwater contamination with several radioactive isotopes (Tompson et al. 2002 ). Among the most important isotopes, there are the 239–240 Pu isotopes, because it was observed that they can be involved in groundwater’s hydrodynamic processes (with the risk of reaching the surface) (Smith and Williams 2005 ). Another problem of underground tests is related to accidental atmospheric contamination with certain radioactive isotopes, as a result of venting. For instance, it is estimated that, out of the total number of approx. 800 underground tests performed in the Nevada Test Site, considerable quantities of radionuclide 131 I were released into the atmosphere through venting in at least the 32 known cases of underground tests (UNSCEAR 1993 ).

The Soviet Union/Russia is responsible for conducting 35 % (715 tests) of the total number of nuclear tests worldwide, 65 % of them being conducted in the Semipalatinsk region of Kazakhstan (Fig.  5 ). Specialized studies have shown that, currently the Semipalatinsk region is heavily contaminated with radioactive isotopes, such as 90 Sr, 137 Cs, 239–240 Pu, and 241 Am, the radionuclides present especially in the soil and the vegetation (IAEA 1998a ; Kadyrzhanov et al. 2005 ). It was also found that the local water bodies feature high concentrations of radioactive uranium isotopes ( 234,235,238 U), well above the maximum value of 15 μg/L allowed by the World Health Organization (Yamamoto et al. 2010 ).

The spatial distribution, type, the number, and the period/year of nuclear tests conducted by the Soviet Union/Russia during 1949–1990 (data processing from http://www.ctbto.org/map/ ); and spatial data modeling after digital elevation model, ETOPO1 (data processing from http://www.ngdc.noaa.gov/mgg/global/global.html )

Currently, the former Soviet region of Semipalatinsk (Semey) is the most heavily contaminated among the Soviet nuclear test sites. While the most critically contaminated areas were found to be Ground Zero (the central-northern area of Semipalatinsk) and Lake Balapan (south-eastern central part), significant levels of radioactivity were also recorded in Tel’kem and Sary-Uzan areas (IAEA 1998a ). Although there are no permanent human settlements in Ground Zero and Balapan, it is estimated that the annual effective dose for the people who visit these areas daily is of 10 mSv (compared, for instance, with the worldwide individual average annual dose of 2.4 mSv from all natural sources), and that, in case at some point permanent settlements be established there, the annual exposure will be of approx. 140 mSv (IAEA 1998a ).

Also, following detailed investigations, it was found that radioactive pollution is not only due to Soviet nuclear tests, but also to the nuclear tests conducted by China in the Tarim Basin. Apparently, part of the radioactive dust in the southern part of the Semipalatinsk region, accumulated during 1964–1981, was the result of the nuclear weapons tests conducted by China at Lop Nur. Thus, the additional quantities of radioactive isotopes, such as 137 Cs, 106,103 Ru, 141,144 Ce and 95 Zr, from the China–Kazakhstan border area, are responsible for the increase in the radioactive contamination of the environment (Yamamoto et al. 2004 ) and, according to Yamamoto et al. ( 2004 ), also for the increased incidence of cancers in the local population.

Another site of major importance is Novaya Zemlya, where nearly 20 % of all the Soviet Union’s nuclear testing was carried out (130 nuclear tests) (Fig.  5 ). As nearly 70 % of all tests were atmospheric, substantial amounts of nuclear debris reached the stratosphere (especially in 1961 and 1962), thus entering a global-scale dispersion process. Locally, 137 Cs and 239–240 Pu radionuclides were found to be the main sources of contamination, mainly in marine waters (IAEA 2000 ). In terms of megatonnes, Novaya Zemlya is the site where the most powerful nuclear test ever performed took place—the Tsar test on October 30, 1961 (a total of 50 Mt, of which 1.5 Mt was from fission yield and 48.5 Mt from fusion yield) (UNSCEAR 2000a ).

Nuclear tests with serious contamination effects were also conducted in Eastern Asia, Australia, and the North Pacific (Fig.  6 ). Lop Nur, in western China, stands out among the most heavily contaminated sites, where the 23 nuclear tests conducted during 1964–1980 have generated a number of radioactive isotopes that have contaminated the biggest part of the province of Xianjiang, including eastern Kazakhstan (Yamamoto et al. 2004 ). Currently, it is estimated that due to the prolonged nuclear tests, cancer incidence in the province is approx. 30–35 % higher than the average rate across China (Merali 2009 ).

The spatial distribution, type, the number, and the period/year of nuclear tests conducted in Eastern Asia, Australia, and the North Pacific during 1946–2013 (data processing from http://www.ctbto.org/map/ ); and spatial data modeling after digital elevation model, ETOPO1 (data processing from http://www.ngdc.noaa.gov/mgg/global/global.html )

As regards India and Pakistan, it can be concluded that there are no significant instances of environmental contamination due to the very low number of nuclear tests. However, the United Kingdom is responsible for the radioactive pollution of vast areas of the Australian continent, as a result of the 12 atmospheric nuclear tests (especially resulting in the dispersal of 239 Pu) conducted at Maralinga, Emu Field, and Montebello (UNSCEAR 2000a ) (Fig.  6 ).

One of the biggest environmental disasters from the nuclear tests period was caused by the USA in the North Pacific, this being the case of radioactive contamination in the wake of the Castle Bravo nuclear test on the Bikini atoll, in 1954 (Fig.  6 ). Pollution of marine ecosystems in the region, and particularly the impact on the local population in terms of the drastic increase of thyroid cancer incidence as a result of the population’s exposure to extremely high doses of radiation, were the negative consequences of the most serious episode of radioactive contamination in the history of nuclear weapons testing (Takahashi et al. 2003 ; Simon et al. 2006 ). For a better perspective, the values of absorbed radiation dose recorded were as high as 6 Gy (in the case of Japanese fishing vessel. Lucky Dragon, close to the contaminated area, with 23 people on board), in comparison, for example, with the 1 mGy value of the average individual effective dose of radiation due to natural radioactive materials in the Earth’s crust and cosmic radiations during 1 year (Hundahl 1998 ; Simon et al. 2006 ). However, the dose rate of ionizing radiation due to natural sources varies considerably in the global context, one example being the Earth’s crust, which, in particular situations, may feature high levels of radioactive material, depending on the rock lithology (Ramasamy et al. 2012 ; Ion 2013 ).

Looking at the overall situation, the 23 atmospheric nuclear tests conducted by the United States in this Pacific region have led to the contamination of soil and marine ecosystems, particularly with radionuclides such as 137 Cs (found in marine water, lagoon sediment, and fish), 90 Sr (coral soils), and 239,240 Pu and 241 Am (both being found mainly in coral sediments) (IAEA 1998b ). Regarding human exposure, it is expected that, for a hypothetical group living on the Bikini Island and consuming only locally produced food, the annual effective dose will be of approx. 15 mSv (mainly from 137 Cs) or 17.4 mSv, if the average annual effective dose due to all natural sources of radiation is included (IAEA 1998b ).

Other cases of intense radioactive pollution of marine ecosystems are represented by the French nuclear tests carried out during 1966–1996 in French Polynesia, more specifically on the Moruroa and Fangataufa atolls, in the south-eastern part of the Tuamotu-Gambier archipelago. France conducted 179 nuclear tests on the Moruroa atoll alone, 42 of them in the atmosphere and 137 in the underground, making this site the third in the world in terms of the most number of nuclear weapons tests, after the Nevada Test Site, and Semipalatinsk. In Fangataufa, the number of nuclear tests was much lower (14 tests: 4 in the atmosphere and 10 in underground), but the carrying out of the biggest French thermonuclear test in 1968 (the Canopus test) caused a serious radioactive contamination, especially in the marine environment. According to specialized research, in the case of the release of radionuclides in marine ecosystems, the negative effects consist foremost in the accumulation of radionuclides in the biota (Erichsen et al. 2013 ), and later in the food chain (Kryshev and Ryabov 2000 ; Koulikov and Meili 2003 ).

Currently, radioactive pollution of the two atolls is mainly due to radionuclides 238,239,240 Pu released in large quantities and, to a lesser extent, to radionuclides 3 H, 90 Sr 137 Cs, 241 Am and 125 Sb (IAEA 1998c ; Livingston and Provinec 2000 ). While the highest concentrations of radioactive 239,240 Pu isotopes were found in atoll lagoon sediments, in terms of human exposure, plutonium-related radiation effects are negligible, given the low rate of transfer to people through feasible pathways (IAEA 1998c ). Although the atolls were also exposed to sizeable amounts of 137 Cs, with peaks in the Kilo-Empereur area of the Fangataufa atoll, an estimated annual effective dose for a hypothetical group living in this area would be of only 0.25 mSv, significantly lower than the annual effective dose of 2.4 mSv, resulting from all natural sources (IAEA 1998c ).

However, the increased incidence of thyroid cancer in the local population (in the Tuamotu-Gambier archipelago, the Austral, Societe and Marquises islands) due to internal irradiation, mainly with radioiodines present in food and water, is an important negative consequence of the nuclear tests conducted by France in the Pacific region (Brindel et al. 2010 ; de Vathaire et al. 2010 ).

French nuclear tests carried out in Algeria from 1960 to 1966 on two major sites, Reggane (four atmospheric tests performed between 1960 and 1961) and Ekker (13 atmospheric tests conducted from 1961 to 1966), led to a significant environmental contamination in North Africa, particularly high in desert sand, mainly due to the release of 239–240 Pu, 137 Cs, and si 90 Sr radionuclides (IAEA 2010 ). Therefore, considering the geographic conditions of the two areas of Algeria, with regard to human exposure, it was found that the main exposure pathways are inhalation and ingestion of contaminated particles (dust), for both underground and atmospheric nuclear tests (IAEA 2010 ).

Human Health Exposure (Thyroid Cancer). Case Study: United States

In terms of human health exposure, specialized studies have shown that thyroid cancer (generally, papillary thyroid cancer) is the most important consequence of nuclear tests, mainly due to radionuclide 131 I (UNSCEAR 2006 ). While the United States is one of the most relevant examples for significant increases in thyroid cancer incidence over the past decades (these increases were influenced to a considerable extent by iodine irradiation) (Gilbert et al. 1998 , 2010 ), similar ascending patterns have been identified in other regions of the world too, where the 131 I radionuclide was released during atmospheric nuclear tests.

According to the National Cancer Institute (NCI 1997a ), 99 % of the 131 I released (150 MCi) during the U.S. nuclear tests is due to atmospheric nuclear tests conducted in the Nevada Test Site, especially between 1951 and 1958. Although it has a low half-life (8 days), it caused the contamination of the American population through rainfall runoff, ground storage (Fig.  7 d), and biosphere transfer (by grassland accumulation). Outstanding cases of radioactive soil contamination were recorded in the states of Nevada, Utah, Colorado, Wyoming, and northern Arizona, and New Mexico (over 370 kBq/m 2 ), with a noticeable radioactivity decrease over distance from the Nevada Test Site.

The composite climatic parameters of wind direction and speed in the United States during 1951–1958, at different heights of the atmosphere (by atmospheric pressure), respectively 3 km (about 700 mb, after the model of a standard atmospheric pressure) ( a ); 7 km (about 400 mb) ( b ); and 12 km (about 200 mb) height ( c ) (data processing from http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/printpage.pl ); total 131 I ground deposition ( d ) for all atmospheric nuclear tests (data processing from NCI 1997b ); and total average per capita cumulative thyroid dose (attributable to 131 I contamination) ( e ) resulting from all exposure routes from all atmospheric tests (data processing from http://www.cancer.gov/cancertopics/causes/i131/stateandcountyexposure )

This is explained by the air-mass dynamics of the 1951–1958 time period (during which the highest release of 131 I radioactive debris was recorded), with dominant west-to-east air-mass movements (Fig.  7 a–c). This shift occurred at different altitude thresholds of the atmosphere (even in the tropopause, above 10 km) and prompted a regional 131 I radionuclide dispersion process (Hundahl 1998 ). The Simon test (April 25th, 1953) is a relevant example, which released large amounts of radioactive debris, with the top of the radioactive cloud reaching a 13.7-km atmospheric height. In this instance, 80 % of the 131 I activity contained in the radioactive debris was estimated to be between 9.5 km and 13.7 km (where, due to higher wind speeds, the radioactive dust dispersion process was accelerated), 10 % was between 9.5 km and ground level, and the remaining 10 % was deposited as the local fallout (NCI 1997a ). Therefore, wind characteristics at different levels of the troposphere (the example of Figs.  7 a, b, c) and the dominant west–east wind shift have resulted in the rapid dispersion of 131 I radioactive dust over long distances and the contamination of vast territories, at least at a regional scale, during atmospheric nuclear tests.

However, the fact that there are certain spatial differences between the 131 I radioactive dust deposited at ground level (Fig.  7 d) and the cancer thyroid dose values of the population (Fig.  7 e) must be acknowledged. According to the NCI report (NCI 1997b , c , d ), the initial radionuclide retention by vegetation (especially by the grass one), the territorially-differentiated consumption levels by cows, and especially the contaminated milk processing–distribution–consumption mechanism dynamics in the United States (particularly during the fifth decade of the last century), represent the main causes for the spatial inconsistencies between the radioactive soil contamination and the irradiation of the population. Therefore, one of the most important transmission vectors of the radioactive isotope in question, especially between 1950 and 1960, was the large-scale contaminated milk distribution–consumption process in the United States, which affected even certain regions of the country’s East Coast. At the same time, the population irradiation process was amplified through the reinforcement of national-scale long-distance milk transportation and distribution patterns, as a result of the widespread use of refrigerated trucks and the reduced transportation costs in this decade (NCI 1997d ).

Therefore, considering certain variables such as age categories during exposure, geographic regions (with regard to contamination sources), and regional dietary patterns, detailed analyses have shown that the highest average per capita cumulative thyroid doses (expressed in milligray) were found in the states of Idaho, Montana, Utah, Colorado, and South Dakota (over 90 mGy) (Fig.  7 e). Moreover, another nine states recorded high values of thyroid doses, namely over 60 mGy. In order to get a better perspective on the facts, by summing up an annual average of approx. 1 mGy of the individual effective dose of radiation due to natural sources (cosmic and terrestrial gamma rays) over a 10-year time period, according to a method that is similar to that used for computing the cumulative dose during atmospheric nuclear tests—a 10 mGy cumulative dose is obtained, which is significantly lower than the dose surplus arising from the 131 I contamination in the aforementioned states (Hundahl 1998 ).

This surplus of the thyroidal dose could be responsible for the increase in the incidence of thyroidal cancer over the last decades, at least for the severely affected states (Fig.  8 ). In this case, the incidence rate can be considered a relevant indicator, as thyroidal cancer is usually characterized by morbidity and hardly ever by mortality.

Thyroid cancer incidence in Utah (1990–2009), Idaho (1999–2010), Montana (1999–2009), Wyoming (2000–2010), Colorado (1995–2009), Nebraska (1999–2009), Kansas (2000–2009), Minnesota (1988–2009), Iowa (1973–2010), Missouri (1999–2009), Arkansas (1996–2010), and Illinois (1999–2009). Rates are per 100 000 population, age-adjusted to the 2000 United States standard population. Data processing sources’: Utah, Iowa, and Arkansas ( http://www.cancer-rates.info/ ); Idaho ( http://www.idcancer.org/ ); Montana, Nebraska, Missouri, and Illinois ( http://apps.nccd.cdc.gov/uscs/ ); Wyoming ( http://www.health.wyo.gov/phsd/wcsp/ annualreport.html); Colorado ( http://www.colorado.gov/cs/Satellite/CDPHE-PSD/CBON/1251627044620 ); Kansas ( http://www2.kumc.edu/kcr/zsearch.aspx ); and Minnesota ( http://www.health.state.mn.us/divs/hpcd/cdee/mcss/ )

By analyzing the thyroid incidence dynamics over the recent decades (or over the last decade only, depending on the available data), it was found that, while all the case studies indicated significant increases, clear growth patterns could be noticed in female subjects (who are more prone to this type of cancer) in the following states: Utah (from 10 per 100 000 in 1990 to 29.4 per 100 000 in 2009), Idaho (from 8.5 per 100 000 in 1999 to 26.1 per 100 000 in 2010), Wyoming (from 7.7 per 100 000 in 2000 to 25.1 per 100 000 in 2010), and Iowa (from 4.3 per 100 000 in 1973 to 18.6 per 100 000 in 2010) (Fig.  8 ). Apparent ascending patterns were also found in Nebraska, Colorado, and Minnesota. Therefore, it can be asserted that, while there is a certain connection between the average per capita cumulative thyroid dose values and the thyroidal cancer incidence rate increase in the analyzed states, it can only be attributed to 131 I to a certain extent. The significant rise of thyroidal incidents can also be closely related to the therapeutic radiation treatments or other risk factors (mostly connected to medical procedures) which have become increasingly perceivable over the last three decades not only in the United States, but also on a global scale (Chen et al. 2009 ; Pellegriti et al. 2013 ).

As a result, while it is cumbersome to correctly determine which risk factors were responsible for the thyroidal cancer incidence increase over the past decades, most studies have shown that therapeutic radiation treatments and environmental exposure to 131 I from atmospheric nuclear testing are the most important risk factors. In a global context, the Chernobyl accident may have been an additional important cause of thyroidal cancer incidence increase in the United States, over the recent decades.

Also, with regard to population exposure to thyroidal cancer risks from 131 I, it is presently significantly lower, and only certain categories of people present a higher incidence risk. These categories depend mostly on variables such as their age at exposure (generally, children up to 10 years of age were the highest risk category during atmospheric nuclear tests), their location between 1951 and 1962, their main diet, their source of milk (as cow milk was the main contamination source), and the amount of milk consumed (Lyon et al. 2006 ). Therefore, the age at exposure is one of the most important variables, as people exposed to radioactive iodine as children may present a high thyroidal cancer risk even decades after the cessation of atmospheric nuclear testing.

Conclusions

The nuclear tests conducted in the second half of the twentieth century had a predominant geopolitical characteristic (part of the nuclear programs of the great powers, a means for the nuclear states to reassert their position on the global geopolitical stage), but with serious ecological and social consequences. From the ecological point of view, at this stage, there are a few critically contaminated test sites both on land (the Nevada Test Site, Semipalatinsk) and in the marine environment (especially the Bikini, Enewetak, Moruroa, Fangataufa atolls, and Novaya Zemlya marine areas). 137 Cs, 90 Sr, 239–240 Pu, 241 Am, and 131 I stand out among the radioactive isotopes released during nuclear tests, in terms of having caused a major impact on the environment and irradiation of the human body; these isotopes were predominantly found in most of the nuclear test sites worldwide. Since approximately two thirds of the Globe’s surface is covered by water, a significant share of these radionuclides has been transferred into the marine environment, as in the cases of radionuclides 137 Cs and 90 Sr, with negative consequences being primarily related to the bioaccumulation through food chain cycles.

The indirect transfer of radionuclides into the geospheres and their accumulation in living cells, by way of the food chain, was yet another form of radioactive contamination of the marine and terrestrial ecosystems. One of the most representative examples is the isotope 14 C released into the atmosphere during nuclear tests, which is later integrated into the CO 2 , and then reaches the marine environment, by means of the ocean–atmosphere gas exchange, or the biosphere through the process of photosynthesis.

In terms of human exposure, the increase in the thyroidal cancer incidence in many areas of the globe (strongly affected by the radioactive contamination with the 131 I radionuclide) is the one among the worst consequences of nuclear testing. This paper’s case study, the United States, could be a relevant example, as a significant thyroidal cancer incidence increase can be noticed in the most severely affected states. However, determining to what extent this radionuclide had influenced the incidence dynamics is not easily accomplishable, given the fact that the development of various therapeutic radiation treatments over the recent decades represents another major cause for the increase in the thyroidal cancer incidence in the United States.

is a doctoral candidate at the Faculty of Geography, Bucharest University. His central work is concerned with interdisciplinary environmental, climatology, and hydrology research.

• Aarkrog A. Input of anthropogenic radionuclides into the World Ocean. Deep Sea Research Part II: Topical Studies in Oceanography. 2003; 50 (17–21):2597–2606. doi: 10.1016/S0967-0645(03)00137-1. [ CrossRef ] [ Google Scholar ]
• Brindel P, Doyon F, Bourgain C, Rachedi F, Boissin JL, Sebbag J, Shan L, Bost-Bezeaud F, Petitdidier P, Paoaafaite J, Teuri J, de Vathaire F. Family history of thyroid cancer and the risk of differentiated thyroid cancer in French Polynesia. Thyroid. 2010; 20 :393–400. doi: 10.1089/thy.2009.0350. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Chen AY, Jemal A, Ward EM. Increasing incidence of differentiated thyroid cancer in the United States, 1988–2005. Cancer. 2009; 115 (16):3801–3807. doi: 10.1002/cncr.24416. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• CTBT. 1996. Comprehensive Nuclear-Test-Ban Treaty (treaty text). http://www.ctbto.org/fileadmin/content/treaty/treaty_text.pdf . Retrieved January 25, 2013.
• Currie KI, Brailsforld G, Nichol S, Gomez A, Sparks R, Lassey KR, Riedel K. Tropospheric 14 CO 2 at Wellington, New Zealand: The world’s longest record. Biogeochemistry. 2011; 104 :5–22. doi: 10.1007/s10533-009-9352-6. [ CrossRef ] [ Google Scholar ]
• Czeplak G, Junge C. Studies of interhemispheric exchange in the troposphere by a diffusion model. Advances in Geophysics. 1974; 18 :57–72. doi: 10.1016/S0065-2687(08)60571-3. [ CrossRef ] [ Google Scholar ]
• de Vathaire F, Drozdovitch V, Brindel P, Rachedi F, Boissin J-L, Sebbag J, Shan L, Bost-Bezeaud F, et al. Thyroid cancer following nuclear tests in French Polynesia. British Journal of Cancer. 2010; 103 :1115–1121. doi: 10.1038/sj.bjc.6605862. [ PMC free article ] [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Erichsen AC, Konovalenko L, Møhlenberg F, Closter RM, Bradshaw C, Aquilonius K, Kautsky U. Radionuclide transport and uptake in coastal aquatic ecosystems: A comparison of a 3D dynamic model and a compartment model. AMBIO. 2013; 42 :464–475. doi: 10.1007/s13280-013-0398-2. [ PMC free article ] [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Fedchenko, V., and R.F. Hellgren. 2007. Nuclear arms control and non-proliferation (Appendix 12B. Nuclear explosions, 1945–2006). http://www.sipri.org/yearbook/2007/files/SIPRIYB0712B.pdf . Retrieved January 25, 2013.
• Gilbert ES, Tarone R, Bouville A, Ron E. Thyroid cancer rates and 131 I doses from Nevada atmospheric nuclear bomb tests. Journal of the National Cancer Institute. 1998; 90 (21):1654–1660. doi: 10.1093/jnci/90.21.1654. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Gilbert ES, Huang L, Bouville A, Berg CD, Ron E. Thyroid cancer rates and 131 I doses from Nevada atmospheric nuclear bomb tests: An update. Radiation Research. 2010; 173 :659–664. doi: 10.1667/RR2057.1. [ PMC free article ] [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Goodby J. The Limited Test Ban Negotiations, 1954–63: How a negotiator viewed the proceedings. International Negotiation. 2005; 10 :381–404. doi: 10.1163/157180605776087507. [ CrossRef ] [ Google Scholar ]
• Goodsite ME, Rom W, Heinemeier J, Lange T, Ooi S, Appleby PG, Shotyk W, van der Knapp WO, Lohse C, Hansen TS. High-resolution AMS 14 C dating of post-bomb peat archives of atmospheric pollutants. Radiocarbon. 2001; 43 (2B):495–515. [ Google Scholar ]
• Grandin K, Jagers P, Kullander S. Nuclear energy. AMBIO. 2011; 39 :26–30. doi: 10.1007/s13280-010-0061-0. [ PMC free article ] [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Grotto A. Why do states that oppose nuclear proliferation resist new nonproliferation obligations?: Three logics of nonproliferation decision-making. Journal of International & Comparative Law. 2010; 18 (1):1–44. [ Google Scholar ]
• Hamilton, T.F., J.C. Milliès-Lacroix, and G.H. Hong. 1996. 137 Cs ( 90 Sr) and Pu isotopes in the Pacific Ocean: Sources and trends. In Radionuclides in the oceans: inputs and inventory , ed. P. Guéguéniat, P. Germain, and H. Métivier, 29–58. Paris: Les Editions de Physique. http://www.osti.gov/scitech/servlets/purl/621645 . Retrieved October 15, 2013.
• Högberg L. Root causes and impacts of severe accidents at large nuclear power plants. AMBIO. 2013; 42 :267–284. doi: 10.1007/s13280-013-0382-x. [ PMC free article ] [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Hundahl SA. Perspective: National Cancer Institute summary report about estimated exposures and thyroid doses received from iodine 131 in fallout after Nevada atmospheric nuclear bomb tests. CA: A Cancer Journal for Clinicians. 1998; 48 (5):285–298. [ PubMed ] [ Google Scholar ]
• IAEA. 1995. Sources of radioactivity in the marine environment and their relative contributions to overall dose assessment from marine radioactivity (MARDOS). IAEA-TECDOC-838, Vienna. http://www-pub.iaea.org/MTCD/publications/PDF/te_838_web.pdf . Retrieved September 21, 2013.
• IAEA. 1998a. Radiological conditions at the Semipalatinsk Test Site, Kazakhstan: Preliminary assessment and recommendations for further study (STI/PUB/1063). http://www-pub.iaea.org/MTCD/Publications/PDF/Pub1063_web.pdf . Retrieved October 20, 2013.
• IAEA. 1998b. Radiological conditions at Bikini atoll: Prospects for resettlement (STI/PUB/1054). http://www-pub.iaea.org/MTCD/Publications/PDF/Pub1054_web.pdf . Retrieved October 22, 2013.
• IAEA. 1998c. The radiological situation at the atolls of Mururoa and Fangataufa: Main report (STI/PUB/1028). http://www-pub.iaea.org/MTCD/Publications/PDF/Pub1028_web.pdf . Retrieved October 24, 2013.
• IAEA. 2000. Global marine radioactivity database (GLOMARD). IAEA-TECDOC-1146, Vienna. http://www-pub.iaea.org/MTCD/publications/PDF/te_1146_prn.pdf . Retrieved September 29, 2013.
• IAEA. 2010. Radiological conditions at the former French nuclear test sites in Algeria: Preliminary assessment and recommendations (STI/PUB/1215). http://www-pub.iaea.org/MTCD/Publications/PDF/Pub1215_web_new.pdf . Retrieved October 24, 2013.
• IAEA. 2012. Fukushima Daiichi status report. http://www.iaea.org/newscenter/focus/fukushima/statusreport280612.pdf . Retrieved September 25, 2013.
• Ion A. Relationship from geology and radon in outdoor air in Massif Ditrău area, Eastern Carpathians—Romania. Carpathian Journal of Earth and Environmental Sciences. 2013; 8 (2):163–168. [ Google Scholar ]
• Kadyrzhanov KK, Khazhekber S, Solodukhin VP, Lukashenko SN, Kazachevskiy IV, Rofer Ch, Poznyak VL, Knyazev BB, et al. Plutonium at the Semipalatinsk Nuclear Test Site (SNTS) Journal of Radioanalytical and Nuclear Chemistry. 2005; 263 (1):229–234. doi: 10.1007/s10967-005-0041-1. [ CrossRef ] [ Google Scholar ]
• Katz JI. Lessons learned from nonproliferation successes and failures. Comparative Strategy. 2008; 27 (5):426–430. doi: 10.1080/01495930802358398. [ CrossRef ] [ Google Scholar ]
• Koulikov AO, Meili M. Modelling the dynamics of fish contamination by Chernobyl radiocaesium: An analytical solution based on potassium mass balance. Journal of Environmental Radioactivity. 2003; 66 :309–326. doi: 10.1016/S0265-931X(02)00134-0. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Krakauer NY, Randerson JT, Primeau FW, Grauber N, Menemenlis D. Carbon isotope evidence for the latitudinal distribution and wind speed dependence of the air–sea gas transfer velocity. Tellus. 2006; 58B :390–417. doi: 10.1111/j.1600-0889.2006.00223.x. [ CrossRef ] [ Google Scholar ]
• Kryshev AI, Ryabov IN. A dynamic model of 137 Cs accumulation by fish of different age classes. Journal of Environmental Radioactivity. 2000; 50 :221–233. doi: 10.1016/S0265-931X(99)00118-6. [ CrossRef ] [ Google Scholar ]
• Levin, I., B. Kromer, H. Schoch-Fischer, M. Bruns, M. Münnich, D. Berdau, J.C. Vogel, and K.O. Münnich. 1994. δ 14 CO 2 record from Vermunt. In Trends: A compendium of data on global change . Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge.
• Levin I, Naegler T, Kromer B, Diehl M, Francey RJ, Gomez-Pelaez AJ, Steele LP, Wagenbach D, Weller R, Worthy DE. Observations and modelling of the global distribution and long-term trend of atmospheric 14 CO 2 . Tellus. 2010; 62B :26–46. doi: 10.1111/j.1600-0889.2009.00446.x. [ CrossRef ] [ Google Scholar ]
• Livingston HD, Provinec PP. Anthropogenic marine radioactivity. Ocean and Coastal Management. 2000; 43 :689–712. doi: 10.1016/S0964-5691(00)00054-5. [ CrossRef ] [ Google Scholar ]
• Lyon JL, Alder SC, Stone MB, Scholl A, Reading JC, Holubkov R, Sheng X, White GL, et al. Thyroid disease associated with exposure to the Nevada nuclear weapons test site radiation. A reevaluation based on corrected dosimetry and examination data. Epidemiology. 2006; 17 (6):604–614. doi: 10.1097/01.ede.0000240540.79983.7f. [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Magnarella PJ. Attempts to reduce and eliminate nuclear weapons through the nuclear non-proliferation treaty and the creation of nuclear-weapon-free zones. Peace & Change. 2008; 33 (4):507–521. doi: 10.1111/j.1468-0130.2008.00516.x. [ CrossRef ] [ Google Scholar ]
• Manning, M.R., and W.H. Melhuish. 1994. Atmospheric δ 14 C record from Wellington. In Trends: A compendium of data on global change . Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge.
• Mastny V. The 1963 Nuclear Test Ban Treaty. Journal of Cold War Studies. 2008; 10 (1):3–25. doi: 10.1162/jcws.2008.10.1.3. [ CrossRef ] [ Google Scholar ]
• McDonnell T. Nuclear pursuits: Non-P-5 nuclear-armed states, 2013. Bulletin of the Atomic Scientists. 2013; 69 (1):62–70. doi: 10.1177/0096340212470816. [ CrossRef ] [ Google Scholar ]
• Merali, Z. 2009. Did China’s nuclear tests kill thousands and doom future generations? Scientific American Magazine . http://www.scientificamerican.com/article.cfm?id=did-chinas-nuclear-tests . Retrieved February 12, 2013.
• NCI. 1997a. Estimated exposures and thyroid doses received by the American people from iodine-131 in fallout following Nevada atmospheric nuclear bomb tests (Chapter 2—History of the Nevada Test Site and nuclear testing background), a report from the National Cancer Institute . Washington, DC: U.S. Department of Health and Human Services. http://www.cancer.gov/i131/fallout/Chapter2.pdf . Retrieved October 3, 2013.
• NCI. 1997b. Estimated exposures and thyroid doses received by the American people from iodine-131 in fallout following Nevada atmospheric nuclear bomb tests (Chapter 3—Deposition of 131 I on the ground), a report from the National Cancer Institute. Washington, DC: U.S. Department of Health and Human Services. http://www.cancer.gov/i131/fallout/Chapter3.pdf . Retrieved October 5, 2013.
• NCI. 1997c. Estimated exposures and thyroid doses received by the American people from iodine-131 in fallout following Nevada atmospheric nuclear bomb tests (Chapter 4—Transfer of 131 I from deposition on the ground to fresh cows’ milk), a report from the National Cancer Institute . Washington, DC: U.S. Department of Health and Human Services. http://www.cancer.gov/i131/fallout/Chapter4.pdf . Retrieved October 8, 2013.
• NCI. 1997d. Estimated exposures and thyroid doses received by the American people from iodine-131 in fallout following Nevada atmospheric nuclear bomb tests (Chapter 5—Cows’ milk production, utilization, distribution and consumption), a report from the National Cancer Institute . Washington, DC: U.S. Department of Health and Human Services. http://www.cancer.gov/i131/fallout/Chapter5.pdf . Retrieved October 10, 2013.
• Pellegriti, G., F. Frasca, C. Regalbuto, S. Squatrito, and R. Vigneri. 2013. Worldwide increasing incidence of thyroid cancer: Update on epidemiology and risk factors. Journal of Cancer Epidemiology . Article ID 965212. doi:10.1155/2013/965212. http://dx.doi.org/10.1155/2013/965212 . Retrieved October 7, 2013. [ PMC free article ] [ PubMed ]
• Prăvălie R. The abolition of the nuclear weapons. A geopolitical and geostrategic problem in the last five decades. Revista Română de Geografie Politică (Romanian Journal of Political Geography) 2012; 2 :143–154. [ Google Scholar ]
• Ramasamy V, Senthil S, Suresh G, Ponnusamy V. Evaluation of gamma radioactivity levels and its radiological hazards of beach and intertidal sediments. Carpathian Journal of Earth and Environmental Sciences. 2012; 7 (4):137–145. [ Google Scholar ]
• Rubinson P. ‘Crucified on a cross of atoms’: Scientists, politics, and the Test Ban Treaty. Diplomatic History. 2011; 35 (2):283–319. doi: 10.1111/j.1467-7709.2010.00950.x. [ CrossRef ] [ Google Scholar ]
• Sauer T. The nuclear nonproliferation regime in crisis. Peace Review: A Journal of Social Justice. 2006; 18 (3):333–340. doi: 10.1080/10402650600848274. [ CrossRef ] [ Google Scholar ]
• Schenck LM, Youmans RA. From start to finish: A historical review of nuclear arms control treaties and starting over with the new start. Journal of International & Comparative Law. 2012; 20 (2):399–435. [ Google Scholar ]
• Scourse JD, Wanamaker AD, Weidman C, Heinemeier J, Reimer PJ, Butler PG, Witbaard R, Richardson CA. The marine radiocarbon bomb pulse across the Temperate North Atlantic: A compilation of Δ 14 C time histories from Arctica islandica growth increments. Radiocarbon. 2012; 5 (2):165–186. doi: 10.2458/azu_js_rc.v54i2.16026. [ CrossRef ] [ Google Scholar ]
• Simon, S.L., A. Bouville, and C.E. Land. 2006. Fallout from nuclear weapons tests and cancer risks. http://www.cancer.gov/PublishedContent/Files/cancertopics/causes/i131/fallout.pdf . Retrieved January 25, 2013.
• Smith DK, Williams RW. The dynamic movement of plutonium in an underground nuclear test with implications for the contamination of groundwater. Journal of Radioanalytical and Nuclear Chemistry. 2005; 263 (2):281–285. doi: 10.1007/s10967-005-0049-6. [ CrossRef ] [ Google Scholar ]
• Stuiver M, Polach HA. Discussion: Reporting of 14 C data. Radiocarbon. 1977; 19 (3):355–363. [ Google Scholar ]
• Takahashi T, Schoemaker MJ, Trott KR, Simon SL, Nakashima KFN, Fukao A, Saito H. The relationship of thyroid cancer with radiation exposure from nuclear weapon testing in the Marshall Islands. Journal of Epidemiology. 2003; 13 :99–107. doi: 10.2188/jea.13.99. [ PMC free article ] [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Tompson AFB, Bruton CJ, Pawloski GA, Smith DK, Bourcier WL, Shaumaker DE, Kersting AB, Carle SF, Maxwell RM. On the evaluation of groundwater contamination from underground nuclear tests. Environmental Geology. 2002; 42 :235–247. doi: 10.1007/s00254-001-0493-8. [ CrossRef ] [ Google Scholar ]
• UNSCEAR. 1982. Report to the general assembly (ANNEX E—Exposures resulting from nuclear explosions). http://www.unscear.org/unscear/en/publications/1982.html . Retrieved January 5, 2013.
• UNSCEAR. 1988. Report to the general assembly (Annex D—Exposures from Chernobyl accident). http://www.unscear.org/docs/reports/1988/1988i_unscear.pdf . Retrieved September 25, 2013.
• UNSCEAR. 1993. Report to the general assembly (Annex B—Exposures from man-made sources of radiation). http://www.unscear.org/docs/reports/1993/1993c_pages%2091-120.pdf . Retrieved September 25, 2013.
• UNSCEAR. 2000a. Report to the general assembly (Annex C—Exposures to the public from man-made sources of radiation). http://www.unscear.org/docs/reports/annexc.pdf . Retrieved September 27, 2013.
• UNSCEAR. 2000b. Report to the general assembly (Annex A—Dose assessment methodologies). http://www.unscear.org/docs/reports/annexa.pdf . Retrieved September 27, 2013.
• UNSCEAR. 2006. Report to the general assembly (Annex A—Epidemiological studies of radiation and cancer). http://www.unscear.org/docs/reports/2006/07-82087_Report_Annex_A_2006_Web_corr.pdf . Retrieved October 2, 2013.
• van der Meer S. Not that bad: Looking back on 65 years of nuclear non-proliferation efforts. Security & Human Rights. 2011; 22 (1):37–47. doi: 10.1163/187502311796365862. [ CrossRef ] [ Google Scholar ]
• Weitz R. Nuclear safety, nuclear security. World Affairs. 2011; 174 (4):56–66. [ Google Scholar ]
• WHO (World Health Organization). 2010. Concise international chemical assessment document 77 (strontium and strontium compounds). http://apps.who.int/iris/bitstream/10665/44280/1/9789241530774_eng.pdf . Retrieved October 20, 2013.
• Yamamoto M, Hoshi M, Takada J, Sakaguchi A, Apsalikov KN, Gusev BI. Current levels and distribution of 137 Cs and Pu isotopes in soil on the Kazakhstan territory of the Kazakhstan–Chinese border: Semipalatinsk and Lob Nor nuclear test sites detonation. Journal of Radioanalytical and Nuclear Chemistry. 2004; 261 (3):533–545. doi: 10.1023/B:JRNC.0000037093.74415.7e. [ CrossRef ] [ Google Scholar ]
• Yamamoto M, Tomita J, Sakaguchi A, Ohtsuka Y, Hoshi M, Apsalikov KN. Uranium isotopes in well water samples as drinking sources in some settlements around the Semipalatinsk Nuclear Test Site, Kazakhstan. Journal of Radioanalytical and Nuclear Chemistry. 2010; 284 :309–314. doi: 10.1007/s10967-010-0463-2. [ PMC free article ] [ PubMed ] [ CrossRef ] [ Google Scholar ]
• Zhu YG, Shaw G. Soil contamination with radionuclides and potential remediation. Chemosphere. 2000; 41 (1–2):121–128. doi: 10.1016/S0045-6535(99)00398-7. [ PubMed ] [ CrossRef ] [ Google Scholar ]

Web References

• Cancer Data Registry of Idaho. http://www.idcancer.org/ . Retrieved October 4, 2013.
• Colorado Central Cancer Registry. http://www.colorado.gov/cs/Satellite/CDPHE-PSD/CBON/1251627044620 . Retrieved October 12, 2013.
• Comprehensive Nuclear-Test-Ban Treaty Organization. http://www.ctbto.org/map/ . Retrieved January 20, 2013.
• Kansas Cancer Registry. http://www2.kumc.edu/kcr/zsearch.aspx . Retrieved October 14, 2013.
• Kentucky Cancer Registry (University of Kentucky). http://www.cancer-rates.info/ . Retrieved October 2, 2013.
• Minnesota Cancer Surveillance System. http://www.health.state.mn.us/divs/hpcd/cdee/mcss/ . Retrieved October 14, 2013.
• National Cancer Institute—State and County Exposure Levels to 131 I. http://www.cancer.gov/cancertopics/causes/i131/stateandcountyexposure . Retrieved October 4, 2013.
• National Geophysical Data Center. http://www.ngdc.noaa.gov/mgg/global/global.html . Retrieved February 5, 2013.
• National Oceanic and Atmospheric Administration, Earth System Research Laboratory—Physical Sciences Division. http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/printpage.pl . Retrieved October 17, 2013.
• National Program of Cancer Registries, United States Cancer Statistics. http://apps.nccd.cdc.gov/uscs/ . Retrieved October 7, 2013.
• Wyoming Cancer Surveillance Program. http://www.health.wyo.gov/phsd/wcsp/annualreport.html . Retrieved October 10, 2013.

Even before Hiroshima, people knew the atomic bomb

Assistant Professor of History, Mississippi State University

Disclosure statement

Matt Lavine does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

Mississippi State University provides funding as a member of The Conversation US.

View all partners

Milton Rothmar, an American Army corporal stationed in Italy, got the news about the Hiroshima bombing from the Armed Forces newspaper Stars and Stripes . He wrote: “The headline said ‘Atomic Bomb.’ To a person who has been raised on stories such as The Final War , this was both a terror and a hope. Man could use this to destroy everything.”

But Rothmar couldn’t suppress his excitement at the prospect that atomic energies might be put to less destructive purposes: “Goddam but it is thrilling to hear the words ‘atomic energy’ used on the radio like they were talking about the latest model car. I feel like shouting to everybody ‘I told you so!’”

His reaction, written down the very day he heard the news, might seem oddly prescient: how did he so quickly understand all the implications and possibilities of what was supposed to be a top-secret weapon?

The answer is that he had been thinking about them for years – and so had many other Americans. The sudden appearance of a real atomic bomb was shocking, but its nature – and the implications of its use – had been talked about for decades. People grappling with the news of Hiroshima did so less by learning new information than by remembering things they had long known.

Fascinated by radioactivity

American newspapers were blaring headlines about Hiroshima within hours of the attack. They were based on an announcement from President Truman that began by describing the astonishing magnitude of the explosion – 2,000 times bigger than anything that had gone before – before explaining that this was possible because the bomb in question “is an atomic bomb. It is a harnessing of the basic power of the universe.”

The surprisingly effective secrecy surrounding the Manhattan Project meant that few were expecting an atomic bomb to appear during the current war. Many who helped make “ Little Boy ” – the bomb dropped on Hiroshima – possibly never knew what they were working on. But what Truman meant by “atomic bomb” was common knowledge.

Long before August 6, 1945, the public had a clear (and surprisingly accurate) idea of the kind of destruction that a bomb based on the liberation of nuclear energies would be capable of. So many writers explored the idea that the early 20th century is sometimes called the “ Radium Age ” of science fiction. Prominent scientists wrote popular books on how to experiment with radioactive substances at home. It was a concept as widely known as the Star Trek warp drive might be today.

The result was an intense public fascination with nuclear energies. Crowds thronged museums to get a glimpse of a speck of radium, thrilled by what newspapers said was a fantastically powerful substance that “leaked” through radioactivity only a tiny fraction of the energy it stored. The great question of the age was whether scientists could find a way to tap that remaining energy, and – if they did – whether they could control it.

Opinions varied.

The case for runaway atomic apocalypses was frequently made by the charter generation of nuclear scientists themselves. Radiochemist Frederick Soddy, in a popular series of lectures , imagined that nuclear energy would allow humanity to “make the whole world one smiling Garden of Eden” – and just as easily, with a single mistake, to destroy it.

Sci-fi to FDR

Radioactive substances attracted popular attention precisely because of those horrifying implications of their seemingly limitless energy. Even what were meant as dispassionate, educational treatments of the subject tended to become lurid.

As historian Spencer Weart has noted , the renowned British physicist William Crookes explained the energy in single gram of radium by saying that it was enough to lift the weight of the entire British navy several thousand feet. The unintentionally violent image of the explosive demolition of a military target caught on in the public discourse. It was the logical conclusion of everything else that the newspapers were printing about the fantastical energies locked away in the atom.

Fiction authors made those implications explicit.

H G Wells coined the term “atomic bomb” in his 1914 novel The World Set Free , which depicted a mid-20th-century war fought with radioactive bombs that exploded – and then kept exploding, poisoning the area with radiation. The novel was dedicated to Soddy, referencing his lectures, and indirectly contributed to real-world nuclear history: it inspired, for example, the physicist Leo Szilard to think about the implications of his theory of neutron chain reactions. Szilard later lobbied FDR to start research on a nuclear program.

Wells was neither the first nor the last author to explore the explosive potential of atomic energies. The comic books, pulp science fiction magazines , and popular science literature of the era were shot through with speculation about atom-powered spaceships and radium bombs and radioactive monsters who gave off mysterious rays.

Some were absurd flights of fancy; others were excellent synopses of current nuclear science. Both sorts had the same effect: to perpetuate the discussion about what the atomic future would look like.

That discourse was often quite optimistic – nuclear medicine and cheap electricity were on people’s minds, too – but bombs were always part of it.

Emotionally fraught

Oddly enough, atomic bombs were discussed more before the war began than during it, thanks in part to wartime paper restrictions that throttled some science fiction magazines.

The technical issues of building a fission weapon were common knowledge even before the war. Less openly talked about was the possibility that those obstacles might be overcome anytime soon. Military censors discouraged magazines from running stories about atomic bombs, although at least one canny publisher argued that they were so common a plot device that to suddenly banish them from print would be to signal the enemy that the United States was making progress on such a weapon.

The months following Hiroshima and Nagasaki were emotionally fraught for Americans: joy at the end of the war mixed uneasily with remorse at the magnitude of destruction and fear that such weapons might someday be used against them.

Atomic bombs and all their moral and technological implications were once again talked about in pulpits, cartoons, newspaper editorials and science fiction. But if it was a more urgent discussion now, it was nevertheless a familiar one.

• Radioactivity
• Radioactive
• Atomic bombs
• Hiroshima and Nagasaki atomic bombs
• atomic energy

Want to write?

Write an article and join a growing community of more than 188,800 academics and researchers from 5,030 institutions.

Register now

• Share full article

Advertisement

Supported by

Biden Approved Secret Nuclear Strategy Refocusing on Chinese Threat

In a classified document approved in March, the president ordered U.S. forces to prepare for possible coordinated nuclear confrontations with Russia, China and North Korea.

By David E. Sanger

David E. Sanger has written about American nuclear strategy for The New York Times for nearly four decades.

President Biden approved in March a highly classified nuclear strategic plan for the United States that, for the first time, reorients America’s deterrent strategy to focus on China’s rapid expansion in its nuclear arsenal.

The shift comes as the Pentagon believes China’s stockpiles will rival the size and diversity of the United States’ and Russia’s over the next decade.

The White House never announced that Mr. Biden had approved the revised strategy, called the “Nuclear Employment Guidance,” which also newly seeks to prepare the United States for possible coordinated nuclear challenges from China, Russia and North Korea. The document, updated every four years or so, is so highly classified that there are no electronic copies, only a small number of hard copies distributed to a few national security officials and Pentagon commanders.

But in recent speeches, two senior administration officials were allowed to allude to the change — in carefully constrained, single sentences — ahead of a more detailed, unclassified notification to Congress expected before Mr. Biden leaves office.

“The president recently issued updated nuclear-weapons employment guidance to account for multiple nuclear-armed adversaries,” Vipin Narang, an M.I.T. nuclear strategist who served in the Pentagon, said earlier this month before returning to academia. “And in particular,” he added, the weapons guidance accounted for “the significant increase in the size and diversity” of China’s nuclear arsenal.

In June, the National Security Council’s senior director for arms control and nonproliferation, Pranay Vaddi, also referred to the document , the first to examine in detail whether the United States is prepared to respond to nuclear crises that break out simultaneously or sequentially, with a combination of nuclear and nonnuclear weapons.

We are having trouble retrieving the article content.

Please enable JavaScript in your browser settings.

Thank you for your patience while we verify access. If you are in Reader mode please exit and  log into  your Times account, or  subscribe  for all of The Times.

Thank you for your patience while we verify access.

Already a subscriber?  Log in .

Want all of The Times?  Subscribe .

latest in US News

5 electrocuted in pool, including teen credited for saving the...

Madeline Soto’s cause of death revealed months after mom's...

Zuckerberg admits Biden admin pressured Facebook to censor COVID...

Mother and 2 men arrested after son, 6, attacked by pit bull...

18-year-old struck and killed by NYC subway train after fleeing...

South Carolina police find body of Massachusetts man who vanished...

New Jersey zoo visitor charged after she's caught on video...

Homeless repeat offender stabs North Carolina tourist across...

Biden secretly orders us to prepare for nuclear threats from china, russia and north korea.

President Biden has signed off on a highly classified plan that shifts America’s nuclear strategy to focus on China as a nuclear threat — and prepare for the possibility that the communist nation could team up with North Korea and Russia against the US, according to a new report.

Biden made the shift in March because the Pentagon believes China’s nuclear arsenal will rival the US and Russia, the New York Times reported Tuesday.

The new strategy is called the “Nuclear Employment Guidance” and also readies the US for a possible coordinated threat between China, Russia and North Korea, the newspaper reported.

In a pair of recent speeches, two senior administration officials have hinted at the growing Chinese nuclear threat.

“The President recently issued updated nuclear weapons employment guidance to account for multiple nuclear-armed adversaries, and, in particular, the significant increase in the size and diversity of [China’s] nuclear arsenal,” said Vipin Narang this month when he was still the acting assistant secretary of defense of space policy.

“My office has begun to provide the Department and the Joint Force updated implementation guidance on how to plan and posture our forces in this new environment.”

He also added during the speech the US hopes China engages “responsibly” on nuclear issues including transparency and risk reduction, which Washington officials have repeatedly raised with the rival nation.

National Security Council’s senior director for arms control and nonproliferation, Pranay Vaddi, also referred to the top-secret document in June, the Times reported.

The new game plan would focus on “the need to deter Russia, the [China] and North Korea simultaneously,” he said, per the newspaper.

US officials believe China’s nuclear force would grow to about 1,000 by 2030 and about 1,500 by 2035, the Times reported.

The US has more than 5,200 nuclear warheads and Russia has a cache of more than 5,800, according to the think tank Federation of American Scientists .

The document, which is updated roughly every four years, is so secretive no electronic copies exist and only a handful of hard copies are given out to a few national security officials and Pentagon commanders, according to the Times.

While a partnership between three adversarial nations that could challenge the US at one time appeared unlikely, Russia and China are now undergoing military exercises together.

North Korea and Iran are giving Russia conventional arms for its war in Ukraine and US officials are trying to figure out if Moscow is in turn helping the pair of countries with their missile programs.

China reportedly used to have a policy of maintaining a “minimum deterrent” before it made the move to accelerate its arsenal that could match or outpace the US government’s stash. North Korea has also expanded its nuclear weapons capabilities, causing concern.

• Work & Careers
• Life & Arts

Nato must wake up to Russia’s nuclear power deal with Turkey

Try unlimited access, only .css-79fz17{-webkit-text-decoration:none;text-decoration:none;} $1 for 4 weeks.

Then $75 per month. Complete digital access to quality FT journalism on any device. Cancel anytime during your trial.

Explore more offers.

Standard digital.

Essential digital access to quality FT journalism on any device. Pay a year upfront and save 20%.

Premium Digital

Complete digital access to quality FT journalism with expert analysis from industry leaders. Pay a year upfront and save 20%.

• Global news & analysis
• Expert opinion
• FT App on Android & iOS
• FT Edit app
• FirstFT: the day's biggest stories
• 20+ curated newsletters
• Follow topics & set alerts with myFT
• FT Videos & Podcasts

Print + Premium Digital

Billed Yearly at $745 . Complete digital access plus the FT newspaper delivered Monday-Saturday.

Terms & Conditions apply

Explore our full range of subscriptions.

Why the ft.

See why over a million readers pay to read the Financial Times.