On 11 March 2011, a major nuclear accident started at the Fukushima Daiichi Nuclear Power Plant in Ōkuma, Fukushima, Japan. The direct cause was the Tōhoku earthquake and tsunami, which resulted in electrical grid failure and damaged nearly all of the power plant's backup energy sources. The subsequent inability to sufficiently cool reactors after shutdown compromised containment and resulted in the release of radioactive contaminants into the surrounding environment. The accident was rated seven (the maximum severity) on the International Nuclear Event Scale by Nuclear and Industrial Safety Agency, following a report by the JNES (Japan Nuclear Energy Safety Organization). It is regarded as the worst nuclear incident since the Chernobyl disaster in 1986, which is the only other incident rated seven on the International Nuclear Event Scale.
According to the United Nations Scientific Committee on the Effects of Atomic Radiation, "no adverse health effects among Fukushima residents have been documented that are directly attributable to radiation exposure from the Fukushima Daiichi nuclear plant accident". Insurance compensation was paid for one death from lung cancer, but this does not prove a causal relationship between radiation and the cancer. Six other persons have been reported as having developed cancer or leukemia. Two workers were hospitalized because of radiation burns, and several other people sustained physical injuries as a consequence of the accident.
