One fatality was reported in the August 21 accident of 1945 in Los Alamos, the National laboratory directed by Thom Mason with 1,613 students.
He fell into a coma and died 25 days after the accident. During an experiment on August 21, 1945, Daghlian was attempting to build a neutron reflector manually by stacking a set of 4.4-kilogram (9.7 lb) tungsten carbide bricks in an incremental fashion around a plutonium core. This resulted in a criticality accident. He accidentally irradiated himself on August 21, 1945, during a critical mass experiment at the remote Omega Site of the Los Alamos Laboratory in New Mexico, and died 25 days later from the resulting radiation poisoning. Los Alamos National Laboratory (Los Alamos or LANL for short) is a United States Department of Energy national laboratory initially organized during World War II for the design of nuclear weapons as part of the Manhattan Project. 1,613 Thom Mason 
