The Hiroshima A-Bomb Black Rain and the Lifespan Study; A Resolution of the Enigma.

The Japanese Lifespan Study (LSS) of the A-Bomb survivors is the principal basis of the current legal radiological framework. Evidence provided for the first time here shows that internal exposure to radiologically significant quantities of Uranium-234 contained in sub-micron particle rainout from the un-fissioned weapon warhead, the Black Rain, is a missing exposure in the LSS analysis. It is argued that this is responsible for a background excess cancer risk in all the LSS dose groups. This, together with epidemiological evidence based on unexposed controls falsifies the LSS cancer vs. dose regression coefficients for internal exposure.