Putting health risks from radiation exposure into context: lessons from past accidents.

1 Department of Surgery and Cancer, Imperial College London Address for Correspondence: Professor Geraldine A Thomas, Department of Surgery and Cancer, Imperial College London, Hammersmith Hospital, Room G02, Du Cane Road, London W12 0HS. Email: [email protected] The response of the international media to the possible health effects of the radiation leaks that occurred at Fukushima, Japan, following the massive earthquake and Tsunami have shown that we have still not learned suffi ciently from the Chernobyl accident. There is still a public perception that any amount of radiation is likely to cause cancer in a substantial fraction of the population. Annual doses from natural radiation vary widely around the world. To have evolved as a successful species, we must be superbly adapted to protecting ourselves from the effects of natural radiation. The problem that we have as scientists is that we rarely expose large populations to increased levels of radiation, so have little evidence to determine risk from exposure above the norm. How much have we learned in terms of risk to human health from the 2 largest exposures of populations to man-made radiation – the atomic bombs in Hiroshima and Nagasaki in 1945 and the Chernobyl Nuclear Power Plant accident in 1986?