Death is swift and sure.
Radiation, on the other hand, is far less predictable. Expose yourself to even a low dose of radiation and it might or might not kill you some time in the future. Epidemiological studies of survivors from Hiroshima and Nagasaki show that people started dying of leukemia five years after the bombs were dropped. It took another 15 years for cancers to develop in the lung, breast and urinary tract. Scientists have used these and other studies to reduce emissions from nuclear plants to levels that they predict will keep the likely number of deaths from radiation-induced disease to a vanishingly small figure.