The immediate horror of Nagasaki and Hiroshima was plain to see–charred bodies and hideously disfigured survivors. Thousands of people who survived soon died because their germ-fighting marrow had been blasted by radiation. And those first deaths–some 180,000 people–initially seemed like just the beginning of the trauma: by 1946, experiments on mice proved that radiation can cause both cancer and genetic defects in the offspring. But now, after 50 years of what is arguably the longest and most comprehensive health study ever undertaken, the scientific consensus holds that the long-term effects on the hibakusha (survivors) and their children have been significantly less than the victims, the public and even scientists expected.
Many survivors did continue to suffer, of course. The Japanese and American scientists of the Radiation Effects Research Foundation reported last year that exposure to the bomb’s radiation increased the frequency of nine forms of cancer, especially leukemia. Among the study group of 86,000 people, the A-bombs caused about 420 more cases of cancer than would have occurred naturally. That’s an added cancer risk of 8 to 12 percent. And 21 of 500 pregnancies underway in August 1945, most notably those in the eighth to 15th week, produced children with severe mental retardation. That’s more than four times the number in healthy mothers. But contrary to the view that the suffering would reverberate through the generations, the number of stillbirths or other birth defects was no higher than in a healthy population. And tests of 72,216 children born more than nine months after the blast show no increase in birth defects, chromosomal abnormalities or cancers. The decades of research have so far failed to find “any significant genetic effects” in the survivors’ children, reported RERF’s Yasuhiko Yoshimoto in 1990. That finding contradicts the widespread fear that the victims would be genetic time bombs, carrying mutated reproductive cells that would cause genetic damage in their children.
Scientists offer several possible explanations for the optimistic findings. One is that humans may simply have better biochemical mechanisms for repairing damage caused by radiation than lab animals do. Or, as RERF reported in 1987, the radiation dose that victims received was less than originally thought; in particular, Little Boy emitted far fewer damaging neutrons than scientists at first calculated. Victims distrust these conclusions, and statistics alone can’t eliminate the fear of the “silent bomb”-especially when Japan adds every survivor’s death, no matter what the cause, to the list of A-bomb martyrs. Nothing will ever remove the physical and psychic pain of the hibakusha, but now, at last, there is hope that the suffering will stop with one generation.
