National Museum of Nuclear Science & History
Staff Sergeant Edward F. O’Mara enlisted in the U.S. Army in 1942. Because of a blood condition, Army officials determined that he was not fit for combat duty.
F. L. Hopkins worked for the Tennessee Eastman Corporation at the Y-12 Plant.
Sanford McDonnell was a mechanical engineer with the Special Engineering Detachment at Los Alamos from April 1944 to April 1946.
Frank R. Johnson was a research assistant at the University of Chicago’s Metallurgical Laboratory (“Met Lab”) during the Manhattan Project.
