After the Chernobyl Disaster at the Chernobyl Nuclear Power Plant on April 26, 1986, hundreds of thousands of workers known as “liquidators” were mobilized by the Soviet Union to contain the disaster. About 600,000 soldiers, engineers, miners, and civilians took part in cleanup operations between 1986 and 1990. Their duties included extinguishing fires, removing radioactive debris, decontaminating buildings, and constructing the concrete sarcophagus over Reactor No. 4. Many received high radiation doses, and thousands later developed serious health problems.