Newly declassified documents reveal that Gen. Leslie Groves—director of the Manhattan Project, the top-secret operation that built the atomic bomb during World War II—misled Congress and the public about the effects of radiation. He did so initially out of ignorance, then denial, and finally, willful deception.
The documents also show that some scientists in the project, including J. Robert Oppenheimer, director of the Los Alamos lab where the bomb was first tested, kept mum about Groves’ lie rather than dispute him or confront the general directly.
The cache of documents—the latest in a series of once secret and top-secret material about the A-bomb obtained over the years by the National Security Archive, a private research organization at George Washington University—was released on Monday, within days of the 78th anniversary of the bombings of Hiroshima and Nagasaki and in the wake of the release of Oppenheimer, the wildly (and deservedly) successful film that has grossed $500 million since its hit theaters just three weeks ago.
One of the new documents the archive obtained is a memo by four scientists, titled “Calculated Biological Effects of Atomic Explosion in Hiroshima and Nagasaki,” dated Sept. 1, 1945. (The bombs were dropped on Aug. 6 and 9 of that year.) Until this memo was written, it had been assumed the A-bomb’s victims would be killed by its blast and its heat. But this memo concluded that at least some of the deaths had been caused by radioactive fallout, days or weeks after the explosions.
And yet, the day before the memo’s date, at a press conference in Oak Ridge, Tennessee, Groves said radiation had caused no deaths and that claims to the contrary—some published in Asian newspapers—were “propaganda.” In a memo to Oppenheimer, George Kistiakowsky, the Los Alamos scientist who coordinated the biological report, said that Groves had “stuck his neck out by a mile,” so he hesitated to pass the study along.
Even by then, enough was known about radiation poisoning to have made Groves stop short of dismissing the claims so strongly. The archive’s documents show that, back in April, three months before the first test of the bomb in New Mexico, medical experts with the Manhattan Project warned of a toxic “cloud” that could spew “radioactive dust” over a wide radius for “hours after the detonation.” Some urged Groves to evacuate the area around the test site, which he resisted, not wanting to attract media attention. One scientist remembered years later that Groves “sniffed” at the warning and said, “What’s the matter with you, are you a Hearst propagandist?” (Hearst was the leading newspaper chain of the day, often specializing in sensational reports.)