National Museum of Nuclear Science & History
J. E. Sampson worked for the United States Engineer District Office.
Twohey worked for Stone and Webster Engineering Corporation.
Gilbert Plass was a Canadian physicist. Plass was born in 1922 in Toronto. He received a B.S. in physics from Harvard University before being hired to work on the Manhattan Project at the Chicago Met Lab, where he worked as an associate physicist.
Merrill Garrett worked at the Y-12 Plant at Oak Ridge, TN during the Manhattan Project. A high school football star, Garrett received an appointment to the United States Military Academy, but was forced to decline due to financial circumstances during the Great Depression.