Condensations of the Carcinogenesis Bioassay Technical Reports.

Caprolactam (aminocaproic lactam, 2-oxohexamethylenimine, CAS No. 105-60-2), the monomer used in the production of nylon-6, was selected and testing initiated by the Carcinogenesis Testing Program, National Cancer Institute (now part of the National Institute of Environmental Health Sciences/National Toxicology Program) because nearly one billion pounds per year are produced, because of the widespread use in food packaging materials and clothing, and because no carcinogenicity studies had been done (1). Nylon 6 resins/fibers are used extensively in carpets, knit fabrics, hosiery, thread, hairbrushes, replacement parts for automobiles and machinery, flotation devices, and food packaging. Highly soluble in water, caprolactam reportedly leaches from clothing made from polyamide fibers when soaked in simulated perspiration (2). Ferguson and Wheeler (3) reported irritation of the skin, eyes, nose, and throat in workers occupationally exposed to caprolactam dust or vapor at concentrations ranging from 10 to 100 ppm.