Uranium ore was processed into weapons-grade plutonium on an industrial scale for the first time in a Mallinckrodt Chemical Co. plant north of downtown St. Louis, Missouri, in December 1942 as part of a secret project.
That first-generation plutonium, which existed on no manifest, was trucked to nearby warehouses along 19-mile Coldwater Creek, loaded onto coal trains bound for Canon City, Colorado, and eventually on to Alamogordo, New Mexico.