The reactions to the radiation leaks at Fukishima make it apparent that we have not learned the lessons of the Chernobyl accident. The two largest exposures to man-made radiation have been in Hiroshima and Nagasaki in 1945, and Chernobyl in 1986.
Atomic bombs killed fifteen to 20% of the population due to acute radiation sickness. Studies of later deaths from cancer show that, of 9335 cancer deaths between 1950 and 1997, 440 deaths were from solid cancers, and 103 cases were the result of leukemia (by 2000). The cancers were the result of radiation exposure and “there are no observable inherited effects in the subsequent generation”. Life expectancies were reduced by 2.6 years for those receiving the highest doses and 21 days for those receiving the lowest doses of irradiation.
The Chernobyl accident resulted in longer exposure of irradiation to humans by ingestion or by breathing radioactive cesium and iodine. The main increase in cancer has been in thyroid cancer in people exposed when they were young, whereas leukemia had been expected. The rates of thyroid cancer have now returned to normal as the isotopes have decayed. Many cases of thyroid cancer may have been prevented if they had been treated with stable iodine at the time of the accident.
Cancer risks from radiation appear to depend on the age of the person at exposure and on the tissues in which the radioactive element settles (such as thyroid). Cancer risks from radioactive cesium appear to be low and cesium does not seem to concentrate in any tissue type.
CONCLUSION: The author believes that there was excessive panic around the time of nuclear disasters and that education of the public about the real risks of radiation is needed.
NOTE: I would, respectfully, argue that we don’t know enough about nuclear disasters and health-related problems to say that people’s fears are not well-founded.