National Museum of Nuclear Science & History
W. J. Cruce worked for the Tennessee Eastman Corporation at the Y-12 Plant.
Twichell worked at 200 West Area at Hanford during the Manhattan Project.
Jack Hefner joined the Manhattan Project at Oak Ridge in 1943. Hefner was a reactor engineer and helped supervise the construction of the X-10 Graphite Reactor.
George Koval was an American chemical engineer and one of the most important Soviet spies of the 20th century.