Operation Crossroads
There were only seven nuclear bombs in existence in July 1946. The two bombs used in the test were Fat Man plutonium implosion-type nuclear weapons of the kind dropped on Nagasaki. The "Able" bomb was stenciled with the name "Gilda" and decorated with an "Esquire" magazine photograph of Rita Hayworth, star of the 1946 movie, "Gilda". The "Baker" bomb was "Helen of Bikini." This femme-fatale theme for nuclear weapons, combining seduction and destruction, is epitomized by the use in all languages, starting in 1946, of "bikini" as the name for a woman's two-piece bathing suit.
Stafford L. Warren
The detonation of the two atomic bombs in Japan "raised as many military and medicomilitary questions as they answered". A series of nuclear tests was planned, codenamed Operation Crossroads. Some 42,000 personnel were deployed to Bikini Atoll as part of Admiral William H. P. Blandy's Joint Task Force 1 to conduct the test. Their health and safety was Lyons's responsibility, but the specialised job of radiological safety was handled by the Manhattan Project. Warren, as Chief of the Radiological Safety Section (RADSAFE), planned and implemented measures to assess, limit and control the impact of radiation. Teams were given special training at Oak Ridge in the operation of instrumentation to measure radioactivity, and the interpretation of their readings. Training was also conducted aboard en route to Bikini Atoll, where it arrived on 12 June 1946. In all, some 3,500 personnel were assigned to RADSAFE. Warren was appalled by the effects of radioactive contamination on the environment. "The deadly range of radioactive products from the atomic bomb has been clearly demonstrated under controlled conditions..." he wrote, "the only defense against atomic bombs still lies outside the scope of science. It is the prevention of atomic war."