National Museum of Nuclear Science & History
Harold Hoover was a member of the Special Engineer Detachment during the Manhattan Project. He worked as a filter foreman at the Y-12 Plant, but his real job was in counterintelligence, to ensure no sabotage occurred.
Charles Cooper was a research associate at the University of Chicago’s Metallurgical Laboratory (“Met Lab”) during the Manhattan Project.
M. E. Russell worked for the Tennessee Eastman Corporation at the Y-12 Plant.