Vinyl Chloride Toxicity

Excerpt

Vinyl chloride monomer is a colorless, gaseous, sweet-smelling organochloride primarily used in the production of polyvinyl chloride. Historically, it was also used as an aerosol propellant and refrigerant before the 1970s. Polyvinyl chloride resins are widely used in building materials, construction, and home furnishings, making them nearly ubiquitous in our society. In 1974, 3 cases of hepatic angiosarcoma—an extremely rare cancer—were identified in workers at a vinyl chloride monomer polymerization plant in Kentucky, prompting an extensive occupational epidemiologic investigation that confirmed vinyl chloride monomer as the causative agent.

Subsequently, the newly formed Occupational Safety and Health Administration (OSHA) lowered the vinyl chloride monomer permissible exposure limit from 500 parts per million (ppm) to 1 ppm with an actionable level of 0.5 ppm, forcing industries to adopt workplace practices to comply. Vinyl chloride monomer is now classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC), confirming the consensus that it is a known carcinogen. In the United States, no cases of vinyl chloride monomer-associated hepatic angiosarcoma are believed to have developed in workers exposed to vinyl chloride monomer exclusively after establishing the 1975 standard.