The Manhattan project that developed and built the world’s first atomic weapon employed some 130,000 people, of which only a small number of women worked as scientists at the famous Los Alamos laboratories in New Mexico. Most of the women and men recruited worked as plant operators who did not know what they were working on until after the bomb was dropped on Hiroshima. Among them were thousands of young women with minimal education and no prior work experience who ran complex machines that separated weapons-grade uranium 235 from uranium 238. They were called the Calutron Girls.

Calutron operators at their panels. Photo: James E. Westcott