1990. It was subsequently removed from the list in 1996 at the request of the manufacturers. In water, caprolactam hydrolyzes to aminocaproic acid, which is used medicinally. As of 2016 caprolactam had the unusual status of being the only chemical in the International Agency for Research on Cancer's lowest hazard category, Group 4: "probably not carcinogenic to humans". Currently, there is no official permissible exposure limit set for workers handling caprolactam in the United States. The recommended exposure limit is set at 1 mg/m3 over an eight-hour work shift for caprolactam dusts and vapors. The short-term exposure limit is set at 3 mg/m3 for caprolactam dusts and vapors. References Epsilon-lactams Monomers Commodity chemicals