A-bomb survivors: reassessment of the radiation hazard

Newly released data from the Radiation Effects Research Foundation on the survivors of the Hiroshima and Nagasaki A-bombing allow a reassessment of radiation hazards. It appears that deaths from marrow damage (such as aplastic anaemia) continued after 1950. The Life Span Study cohort appears biased in favour of persons with high immunological competence, the result of infants and the elderly being more likely to die before 1950 than young adults. A study of survivors of in utero exposures suggests that embryos are more sensitive to the lethal effects of radiation than more mature foetuses. Current estimates of cancer risks from radiation may only apply to young adults with high immunological competence; young children and the elderly may be at greater risk.