Louis Alexander Slotin, was a Canadian physicist and chemist who worked on the Manhattan Project, Slotin was the second person to die from a criticality accident, following the death of Harry Daghlian, who had been exposed to what?
Louis Slotin:  Slotin was the second person to die from a criticality accident, following the death of Harry Daghlian, who had been exposed to radiation by the same core that killed Slotin. Harry Daghlian: Haroutune Krikor "Harry" Daghlian Jr. (May 4, 1921 – September 15, 1945) was a physicist with the Manhattan Project which designed and produced the atomic bombs that were used in World War II.
radiation