National Museum of Nuclear Science & History
Phelps worked in the 100 F Area at Hanford during the Manhattan Project.
Thompson worked for Stone and Webster Engineering Corporation.
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.
D. S. Ewing worked for the Tennessee Eastman Corporation at the Y-12 Plant.
Harry Reason was a janitor at the Metallurgical Laboratory in Chicago during the Manhattan Project.