Neoplastic risk among workers exposed to vinyl chloride.

As early as 1930 the first adverse health effects of vinyl chloride (VC) were reported.' Since then, numerous observations and studies have indicated a wide range of toxicity attributable to the effects of VC on the central nervous system, the liver, the bones of the fingers, and the Lately, the spectrum of known toxic effects of VC broadened to include malignant neoplasms. Viola et al.," in 1971, reported the induction of tumors of the skin, lungs, and bones in rats exposed by inhalation to 30,000 ppm of VC for twelve months. However, widespread acceptance of the carcinogenic activity of VC did not occur until early in 1974 after the announcement of three cases of liver angiosarcoma among workers at a single VC polymerization facility in the U.S.A." About the same time, Maltoni reported the same cancerous hepatic effect in animals following exposure by inhalation to VC.13 Shortly thereafter, Maltoni and Lefemine l 4 and Keplinger et al.15 reported the induction of tumors of the brain, kidney, liver, lung, and lymphatic system in mice, rats, and hamsters exposed to VC by inhalation. Consequently, an epidemiological evaluation was undertaken by the National Institute for Occupational Safety and Health (NIOSH) to assess the magnitude and spectrum of neoplastic effects in workers exposed to VC. This study included industrial hygiene surveys, retrospective cohort analyses of mortality patterns, and histopathologic evaluation of tumors.