Vinyl Chloride Toxicity

Vinyl chloride monomer (VCM) is a colorless, gaseous, sweet-smelling organochloride primarily used in the production of polyvinyl chloride (PVC) with additional historical usage before the 1970s as an aerosol propellant and refrigerant. VCM is now classified as an International Agency for Research on Cancer (IARC) Group 1 carcinogen. PVC resins are used widely in building materials, construction, and home furnishings, making PVC resins nearly ubiquitous in our society. In 1974, three cases of hepatic angiosarcoma (HAS), an extremely rare cancer, in workers at a VCM polymerization plant in Kentucky prompted an extensive occupational epidemiologic investigation that led to the confirmation of VCM as the cause. Subsequently, the newly formed Occupational Safety and Health Administration (OSHA) lowered the VCM permissible exposure limit (PEL) from 500 parts per million (ppm) to 1 ppm with an action level of 0.5 ppm forcing industry to adopt workplace practices to comply. In the United States, no cases of VCM-associated HAS are believed to have developed in workers exposed to VCM exclusively after establishing the 1975 standard.