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VINYL CHLORIDE
CAS No: 75-01-4
I. PHYSICAL AND CHEMICAL PROPERTIES (From HSDB, 1998)
Molecular weight 62.5
Boiling point
-13.37ºC
Melting point
-153.8°C
Vapor pressure 2660 mm Hg @ 25°C
Air concentration conversion 1 ppm = 2.56 mg/m 3
II.
HEALTH ASSESSMENT VALUES
Unit Risk Factor: 7.8 E-5 (µg/m 3 ) -1
Slope Factor: 2.7 E-1 (mg/kg-day) -1
[Female mouse lung tumor incidence (Drew et al., 1983), extra risk calculated using a linearized
multistage procedure (CDHS, 1990).]
III.
CARCINOGENIC EFFECTS
Human Studies
In 1974, Creech and Johnson described three cases of angiosarcoma of the liver (LAS) among workers
at the B.F. Goodrich Tire and Rubber Co. in Louisville, Kentucky. Because LAS is a very rare cancer
(20-25 cases per year in the U. S.), the clustering of three cases in one vinyl chloride (VC)
polymerization facility indicated an abnormally high incidence of this cancer. Based on this report, as
well as data indicating that VC is carcinogenic in laboratory animals, multiple studies of workers
exposed to this agent were conducted. By 1985, at least 15 epidemiologic studies relating VC
exposure to the incidence of various cancers had been completed. A summary of the data from these
studies is provided in Table 1.
Between 1961 and 1977, 23 cases of LAS were reported among approximately 20,000 VC workers
in the U.S. (Lelbach and Marsteller, 1981; Spirtas and Kaminski, 1978). The expected incidence of
LAS is 0.014 cases per 100,000 per year in the general population in the U.S. (Heath et al., 1975).
Based on analysis of these data, the relative risk for developing LAS following VC exposure among this
country’s VC workers is 483.
The epidemiologic studies also demonstrate a strong and consistent association between VC exposure
and primary cancer of the liver. All of the studies that assessed risk for primary liver cancer note a
statistically significant increase in standardized mortality ratios (SMRs). The average relative risk for
liver cancer among VC workers is five to six times greater than the incidence of that seen in the general
population. The evidence strongly suggests that exposure to VC can cause liver cancer. All reports
published to date indicate that the SMRs of exposed workers are elevated, and risk of liver cancer was
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