Studies revise dose estimates of A‐bomb survivors

We know very little about the longterm health hazards of human exposure to neutron irradiation—certainly less than we thought we knew a year ago. The painstaking follow‐up of the Hiroshima and Nagaski survivors has provided our only extensive data on human neutron exposure. A joint Japanese‐American effort has for more than three decades attempted to keep track of the medical history of every person within a few kilometers of Ground Zero who survived the cataclysm and its immediate aftermath in these two ill‐fated cities.