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Kyshtym disaster


The Kyshtym disaster was a radioactive contamination accident that occurred on 29 September 1957 at Mayak, a plutonium production site in Russia for nuclear weapons and nuclear fuel reprocessing plant of the Soviet Union. It measured as a Level 6 disaster on the International Nuclear Event Scale (INES), making it the third-most serious nuclear accident ever recorded, behind the Fukushima Daiichi nuclear disaster and the Chernobyl disaster. The event occurred in Ozyorsk, Chelyabinsk Oblast, a closed city built around the Mayak plant, and spread hot particles over more than 20,000 square miles (52,000 km2), where at least 270,000 people lived. Since Ozyorsk/Mayak was not marked on maps, the disaster was named after Kyshtym, the nearest known town.