CentralNotice From Wikipedia, the free encyclopedia Jump to navigation Jump to search 1957 radiological contamination disaster in the Soviet Union See also: Pollution of Lake Karachay Kyshtym disaster Map of the East Urals Radioactive Trace (EURT): area contaminated by the Kyshtym disaster. Date 29 September 1957 Location Mayak , Chelyabinsk-40 , Chelyabinsk Oblast , Russian SFSR , Soviet Union Coordinates 55°42′45″N 60°50′53″E  /  55.71250°N 60.84806°E  / 55.71250; 60.84806 Coordinates : 55°42′45″N 60°50′53″E  /  55.71250°N 60.84806°E  / 55.71250; 60.84806 Type Nuclear accident Outcome INES Level 6 (serious accident) Casualties 66 diagnosed cases of chronic radiation syndrome [ citation needed ] Estimated 200 additional cases of cancer [ citation needed ] 10,000 evacuated [ citation needed ] The Kyshtym disaster , sometimes referred to as the Mayak disaste...