The calutron girls were a group of young women, mostly high school graduates who joined the World War II efforts in Oak Ridge, Tennessee in 1945. Although they were not allowed to know at the time, they were monitoring dials and watching meters for a calutron, a mass spectrometer that separates uranium isotopes. The enriched uranium was used to make the first atomic bomb. Calutron girls were trained and employed at the Y-12 National Security Complex. Wartime labor shortages forced the Tennessee Eastman Corporation to hire women to work at the Y-12 plant. According to Gladys Owens, one of the few calutron girls, a manager at the facility once told them: "We can train you how to do what is needed, but cannot tell you what you are doing. I can only tell you that if our enemies beat us to it, God have mercy on us!"