National Museum of Nuclear Science & History
A. M. Hartman worked for the Roane-Anderson Company.
Gus Essig began working on the Manhattan Project in May, 1946 in Dayton, Ohio. Essig was selected to work in the highly classified initiator program and spent several months at Los Alamos learning how to design and construct initiators.
Lyle Crowe worked for the J.A. Jones Construction Company.