In May, 2011 the Natural Resources Defense Council estimated that there would be 100 excess cases of cancer among the population of 2 million from the Fukushima nuclear reactors. That was portrayed as a high-end estimate, because it assumed that everyone in the Fukushima area stood outside during the release events and did not take shelter.
Richard Harris, science reporter, talked to Robert Gale and John Boice about the two workers who got reddening on their legs after exposure to excess radiation. (Contaminated water got into their boots). Gale had examined the workers and said the dose caused a localized reaction but is not high enough to pose an ongoing health risk to the workers.
The nuclear fuel in one reactor has probably melted through its vessel and is now apparently sitting on a concrete-and-steel outer containment building. There is no evidence [Richard Harris] knows of that says significant radiation is currently making its way into the environment.
Under ordinary circumstances 40 percent of the Japanese population gets cancer, so a population of 2 million would expect to see 800,000 cases. An excess of 100 deaths over a lifetime would mean an extra one hundreds of one percent or one part in ten thousand.