Duffer Crawford worked for the civilian contractor Kellex Coroporation in New York under the supervision of Judson Swearingen. He helped develop equipment to be used for sealing on the piping of the Oak Ridge, TN facility. Crawford would often be sent to Oak Ridge to help install the parts. Despite the decades that have passed since the end of the Manhattan Project, Crawford was reminded as late as 2008 that some of the seal designs remained classified.
National Museum of Nuclear Science & History
