The Secret PR Push That Shaped the Atomic Bomb's Origin Story

A fear of associating nuclear weapons with poison gas might have influenced which scientists got credit for the “physicists’ bomb.”

In August 1945, a few days after the United States dropped atomic bombs on Hiroshima and Nagasaki, the government released an official report on the history of the destructive weapon. “The work on the atomic bomb,” it explained, was undertaken in Los Alamos, where “an extraordinary galaxy of scientific stars gathered on this New Mexican mesa.” Despite its dull prose, the Smyth report, as it came to be known, would make The New York Times’ bestseller list and be translated into more than three-dozen languages. “J. R. Oppenheimer has been director of the [Los Alamos] laboratory from the start,” it explained.

Emphasizing the contributions of Julius Robert Oppenheimer—the theoretical physicist who is still commonly referred to as the father of the atomic bomb—was routine at the time. Shortly after the success of the first atomic-bomb test in New Mexico, the U.S. Department of War issued a document stating that Oppenheimer “is to be credited with achieving the implementation of atomic energy for military purposes.”

Such clear attribution to a single physicist for the entire Manhattan Project has always been an odd simplification. Physics is at the heart of nuclear-bomb making, yet it is only one of many other areas of science, such as chemistry and engineering, necessary to complete the weapon. Only 4 percent of the Manhattan Project, which developed the bomb, was spent on Los Alamos. So why is the work of scientific disciplines other than physics often missing from the origin story of the bomb?

After reading the Smyth report, the chemist Glenn Seaborg wrote to Henry DeWolf Smyth, the report’s author and a physicist at Princeton. “A large number of chemists, both on and off the Manhattan District program, have pointed out to me the extraordinary brief and undetailed treatment, compared to the treatment of physics problems, given to chemical problems and accomplishments in the ‘Smyth Report,’” Seaborg wrote. He and his colleagues felt utterly “belittled.”

One reason chemistry was omitted could be that the military actively excised certain research topics for reasons of national security: Clearly they should not give away any information that might help the enemy build its own bomb. “Military security prevents this story from being told in full at this time,” explained Leslie Groves, the director of the Manhattan Project, in the foreword to the report. He warned that sharing any additional information about the bomb beyond the official history contained in the Smyth report would incur “severe penalties under the Espionage Act.”

In The Making of the History of the Atom Bomb, Rebecca Press Schwartz has detailed how as a result of the Smyth report and censorship related to the project, historians have heaped praise on a “small band of genius physicists on a mesa of Los Alamos.” Yet close attention to historical documents suggests the military had an additional motive beyond national security for avoiding chemistry-related topics that has been overlooked. Key scientists involved with the development of nuclear weapons had noted their similarity to poison-gas weapons. As the historian Janet Farrell Brodie argues, “American officials did not want the atomic bombs linked with chemical and biological warfare.”

Part of the reason that the atomic bomb became the “physicists’ bomb” was simply the result of a public-relations effort.

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In 1940, Otto Frisch and Rudolf Peierls, Jewish émigrés working in England, were the first to calculate the critical mass of uranium needed for a nuclear bomb. They detailed their insights in a memo to Winston Churchill, theorizing that not only would the bomb’s blast be exceptional, but also that the effects of its “radioactive substances” would be comparable to those of gas weapons: “Radioactivity will be carried along with the wind and will spread the contamination; several miles downwind this may kill people.”

They argued that military personnel entering a recently bombed area should be outfitted with lead vehicles and oxygen tanks “because of the danger from contaminated air” and concluded that the nature of the bomb’s destructive power “may make it unsuitable as a weapon for use by this country.”

The following year, in a report for the National Academy of Sciences, Smyth and the physicist Eugene Wigner said that nuclear reactors produced substances with effects similar to “a particularly vicious form of poison gas.” These comparisons to gas weapons were problematic. The bomb, as destructive as it was, could be an even greater liability if it fell under international restrictions that had already been applied to gas weapons. The Geneva Protocol of 1925, signed by major European powers, prohibited the use of “asphyxiating, poisonous or other gases, and of all analogous liquids, materials or devices.” Poison gas in World War I had been so widely condemned that in 1943 President Franklin D. Roosevelt declared, the “use of such weapons has been outlawed by the general opinion of civilized mankind.”

But James Conant, the chairman of the Manhattan Project, had no qualms against gas weapons. He had developed poison gas working in the Chemical Weapons Service during World War I. Years later in his memoirs, he wrote: “I did not see in 1917, and do not see in 1968, why tearing a man’s guts out by a high-explosive shell is to be preferred to maiming him by attacking his lungs or skin.” The view that gas weapons were less moral than others, he believed, was just plain “old fashioned.”

In 1942, James Franck, a German chemist who emigrated to the U.S., was hired to work in the Manhattan Project as director of the chemistry division of Chicago’s “Metallurgical Lab,” colloquially known as the “gas house.” Franck had ample experience working with poison gas. During World War I, he had been the “confidential assistant” of Fritz Haber, the father of chemical warfare. Alongside the scientists at Chicago, however, he developed serious doubts about the bomb project, and organized secret all-night sessions where his colleagues could voice their concerns. Together, the group drafted a document known as the Franck Report.

“We have large accumulations of poison gas,” this report explained, “but do not use them, and recent polls have shown that public opinion in this country would disapprove of such a use even if it would accelerate the winning of the Far Eastern war.”

The report considered the implications of using the weapon from various angles—moral as well as technical—and recommended against using the bomb without prior warning. When George Harrison, the special assistant to the Secretary of War, Henry Stimson, summarized its main message to his boss, he explained it this way: “They feel that to do so might sacrifice our whole moral position and thus make it more difficult for us to be the leaders in proposing or enforcing any system of international control.”

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The lessons Harrison derived from the Franck report, however, seemed to have more to do with controlling the perception and history of the new weapon than with further investigating any troubling comparisons. Immediately after reading it, Harrison stressed the need to compose “fairly complete statements to the world about [the bomb’s] history and development.” He knew that the effects of the bomb would shock the public, making it harder for civilians to embrace nuclear energy in the post-war period, so he sent a memorandum to Stimson, urging him to act quickly “to avoid the risk of grave repercussions on the public in general and on Congress in particular.”

In a May 31, 1945, meeting with Oppenheimer and other top scientists, Stimson and the Army Chief of Staff George C. Marshall set key directives for subsequent narratives of the bomb and its development. Stimson explained to those present that the atom bomb was a “special” weapon—one arising from elite knowledge, and not from industrial engineering. Accounts of its development were to stress brains, not brawn: “This project should not be considered simply in terms of military weapons,” he said, “but as a new relationship of man to the universe.” The point of comparison was to be that of the Copernican or Newtonian revolutions, but “far more important” than both.

Groves, the Manhattan Project director, for his part, complained during the meeting how the bomb program had “been plagued since its inception by the presence of certain scientists of doubtful discretion and uncertain loyalty.” Immediate “steps should be taken to sever these scientists from the program and to proceed with the general weeding out of personnel no longer needed.”

Groves was well-prepared for shaping how the public understood the bomb. He had already hired Smyth a year earlier to write the official history of the project. Smyth seems like an ideal choice: Not only had he worked in the Chemical Warfare Service as a young man, he had explored the possibility of creating “a particularly vicious form of poison gas” with nuclear-fission materials. The radioactive poisons “produced in one day’s run” of a nuclear reactor, he had concluded, “might be sufficient to make a large area uninhabitable.”

In The Making of the History of the Atom Bomb, Schwartz says that when writing the report, Smyth was placed under armed guard in an office at Princeton University, where he deposited the text in a locked safe at the end of every day. Drafts were delivered directly to Groves by members of the Army.

In one early draft, Smyth toyed with comparing the bomb to poison gas: “Shall we accept this new material as a mere supplementary weapon—just a new kind of bomb? Or shall we consider it like poison gas, too vicious to use unless it is used first against us?” This sentence, among others, was stricken from the final version that was approved by Groves.

The final version instead noted that “Smyth did not recommend the use of radioactive poisons nor has such use been seriously proposed since by the responsible authorities.” No mention was made of the assertions that the bomb’s blast would inevitably come with these poisons, despite clear efforts to separate the two.

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How credible was Groves’s statement, in the Smyth report’s foreword, that “all pertinent scientific information which can be released to the public at this time without violating the needs of national security is contained in this volume”? Scientists not only noted that too much was missing; many of them also did not believe that such notable gaps were warranted for those reasons. Seaborg, the upset chemist who wrote to Smyth after the report was published, did not accept the argument that such censorship was necessary, insisting that the slim accounting of chemistry “cannot be ascribed, except perhaps in part, to security limitations.”

Groves nonetheless enforced a strict censorship agenda. After a scientist who worked in the project wrote an article in The San Francisco Examiner asserting (incorrectly, as it would turn out) that the residual radiation in Hiroshima “will not be dissipated for approximately 70 years,” he was questioned by the FBI and pressured to retract his claims. Groves also tried to suppress the work of an Associated Press science editor who was one of the first Americans to describe the effects of radiation to the public.

Censoring information was as important as providing positive narratives about the bomb’s origin and its history. For this, Groves also hired William Laurence, a New York Times reporter to do PR work about the project. Later, Laurence published Dawn Over Zero: The Story of the Atomic Bomb, which was so effusive about the role of physics in the project that it even identified the bomb’s success with Einstein’s theory of relativity, an area of science so theoretical that scientists could scarcely find more than a few testable effects from it—let alone create any practical applications from it. But relativity was nonetheless readily credited for saving lives.

“Thousands of young Americans thus may owe their lives to the theory of relativity,” Laurence wrote, “which is another way of saying that pure science, no matter how impractical it may appear, pays high dividends in the end.”

Physics-centered narratives like these can help explain why one of the images associated with the bomb became so iconic. To celebrate its first anniversary, Einstein graced the July 1, 1946, Time magazine cover, superposed onto a mushroom cloud engraved with the immortal equation, E=mc².

The elision of the work of certain chemists and other scientists from documents like the Smyth report that continues to this day was to a considerable extent the result of political interests. But more than national security was at stake. Pushing aside chemistry in particular could have been the result of a politically grave danger: associating the bomb with poison gas, widely condemned as a battlefield weapon even by Adolf Hitler.

In a recent article, the atom-bomb historian Sean Malloy argues that, after Hiroshima, Groves “seemed to fear” that the bomb “might easily be grouped with chemical and biological weapons as an inhumane form of warfare” before convincing himself and others that they were entirely different. Malloy concludes that “a combination of ambition, wishful thinking, and a form of ‘self-compartmentalization’” underlined his “bizarre” blindness toward the indiscriminate nature of the bomb’s radiation. Even when Groves was called to testify before a Senate committee a few months after the bombs were dropped, he described radiation as “a very pleasant way to die,” despite having recently read about the harrowing deaths by radiation in Hiroshima.

Privately, Groves considered the physicists he employed in Los Alamos as “the greatest bunch of prima donnas ever seen in one place.” Yet these men would be crowned as the intellectual fathers of a life-saving bomb to the exclusion of their colleagues and the numerous radiation victims of Hiroshima and Nagasaki. It was a great story, one that turned a handful of physicists into heroes and geniuses and erased the bomb’s links to previously outlawed weapons of mass destruction.