The March 11 nuclear accident at the Fukushima No. 1 plant has transformed what used to be a long-standing academic debate into an urgent issue for millions of ordinary people: Will long-term exposure to low-level radiation cause any health problems?
Experts have long been at odds over whether low-level radiation doses of less than 100 millisieverts are damaging.
Following are questions and answers on the effect of low-level radiation on human health: