CW: Historical accounts of violence/injury
First Manhattan Project Report on “Biological Effects” of Atomic Bombs Confirmed Radiation Deaths
Gen. Groves “Stuck His Neck Out a Mile” in Denying Radiation Effects
Los Alamos Official: Bombs “Could Not Have Done More Damage,” Extent of Destruction “Exactly That Predicted”
Washington, D.C., August 7, 2023 – A newly declassified memorandum from the weeks after the atomic bombings of Hiroshima and Nagasaki confirmed early reports of fatal radiation disease even as Manhattan Project director General Leslie Groves characterized the accounts from Japan as “propaganda.” The September 1, 1945, report from staffers at Los Alamos Laboratory on the “Calculated Biological Effects” of the atomic bombings listed death by exposure to gamma ray radiation as one of several possible lethal consequences of the bombings. Senior Los Alamos scientist George Kistiakowsky wrote that Groves had “stuck his neck out a mile” when he denied reports of radiation deaths and apparently refrained from sending him the September 1 memo (Document 21), which contradicted Groves’ assertion.
The memo was published today for the first time as part of an update to last year’s Electronic Briefing Book on how Manhattan Project scientists estimated and calculated the harmful impacts of nuclear radiation while Groves continued to downplay and make misleading statements about its effects. That posting included declassified internal reports on the deadly impact of radiation in the aftermath of the August 1945 bombings. The U.S. National Nuclear Security Administration recently released a copy of the memorandum in response to a Freedom of Information Act (FOIA) request by the National Security Archive.
Also included in today’s update are transcripts of telephone conversations from September 7, 1945, in which Groves continued to deny that the bombings had caused radiation sickness (Document 22); congressional testimony by Los Alamos scientist Philip Morrison on the deadly radiation effects of the atomic bombings (Document 28); and a January 1946 report by William Penney, a British member of the Los Alamos Laboratory staff, who found that the blast damage to Hiroshima and Nagasaki, was “exactly that predicted” by target planners (Document 30).