National Museum of Nuclear Science & History
Robert McCoy worked for the United States Engineer District Office.
Andrew Welch was a janitor at the Chicago Met Lab during the Manhattan Project.
Richard Emanatian was with the military police detachment at Los Alamos during the war. He maintained secrecy through the rest of his life, and his family only found about his involvement long after his death.
F. C. Liepman worked for the Tennessee Eastman Corporation at the Y-12 Plant.