Before the war Oswald Greager was a high-ranking DuPont chemist. He took leave from DuPont in 1942 to join the Army's Chemical Warfare Service. Later, he was transferred to the Manhattan Project. At Hanford, he was the Army's representative at the plutonium separation areas. He returned to Hanford after the war to work for General Electric as a technical manager in the separation areas. He stayed in Richland after retirement.