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.
Chester A. Hammond served as a corporal in the 393rd Bombardment Squadron. He was a member of the ground crew on the B-29 Full House.
Seymour Calvert served for 11 months in the Special Engineering Detachment at Los Alamos. He specialized as a chemical engineer, and carried out experiments with beryllium that were often dangerous.