While Carothers and the other scientists of "Purity Hall" were inventing nylon, Joe Labovsky, the trained industrial chemical engineer, worked as a simple assistant, testing the polymers the scientists would make. The tests were nothing the scientists couldn't do themselves, and Labovsky had doubts about his job security. But Carothers kept him around. His skills would soon be needed.

Once the research and the experimental stage of the development of nylon were complete, the next step was to design a commercial plant that could produce millions of tons of nylon fiber at a relatively low cost. DuPont tested prototype machinery in two trial facilities, the semi-works (1936) and the pilot plant (1938), before full-scale commercial production began in 1939.