In 1955, the Priestley Medal was awarded to Charles A. Thomas by the American Chemical Society “to recognize distinguished services to chemistry,” the Society’s most prestigious award.

Thomas was recruited to join the Manhattan Project in 1942 by General Leslie Groves, the director of the Los Alamos Laboratory in New Mexico. He agreed to coordinate plutonium purification and production at many Manhattan Project locations including Los Alamos, the Met Lab in Chicago, the Radiation Laboratory at Berkeley, and Ames Laboratory in Iowa. In 1943, Thomas was tasked with developing a method to separate polonium, a rare and unusual element which was selected as the “initiator” for the plutionium bomb. Thomas decided to carry out this work in his hometown of Dayton, Ohio.

Before the War, he was a research chemist for General Motors Research Corporation. Thomas and chemist Carroll Hochwalt established Thomas and Hochwalt Laboratories in Dayton. Eventually this company was bought out by Monsanto Chemical Company, and Thomas became Monsanto’s director of central research.