National Museum of Nuclear Science & History
George Cowan joined the Manhattan Project in 1942 at the Met Lab as a chemist for Enrico Fermi’s group, and also worked for Columbia University.
John Vach was a guard at the Metallurgical Laboratory in Chicago during the Manhattan Project.
Rex Edward Keller was a member of the Special Engineering Detachment, assigned to work in Seth Neddermeyer’s chemistry group at Los Alamos.
Ernest K. Clark served in the 1st Ordnance Squadron.