UN experts find 'no harmful effects' from Fukushima nuclear disaster Researchers found that the 2011 nuclear catastrophe had not harmed the health of local residents or increased the risk of cancer, according to a new report. An earthquake and the ensuing tsunami caused the 2011 Fukushima disaster 10 years ago, according to UN report published on Monday. The series of meltdowns and explosions, prompted by a 2011 earthquake and a subsequent tsunami, is considered the world's worst nuclear disaster since Chernobyl in 1986. The nuclear radiation from the Japan accident has not increased the risk for cancer beyond normal, said the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR).