Evidence for low dose effects

The incidence of cancer has been proven by 60 years study of the effects on the victims of the Hiroshima and Nagasaki nuclear explosions (see plot of cancer risk versus dose [Pierce et al 1996]). Although the data is not accurate enough to be certain of effects at very low doses, it is prudent to assume that effects do go down to zero. The data give a very high confidence that doses of order 50 mSv result in the induction of cancer. Doses of this order are not uncommon in medical practice.