home edit2 whole TSD November 2002 PDF format - OEHHA

Data on noncarcinogenic toxic effects of vinyl chloride were sparsely reported in the Maltoni BT
experiments. Vinyl chloride appeared to be toxic at the higher concentrations, but reportedly the high
mortality at these dose levels was due to a high incidence of vinyl chloride-induced tumors. The
available information on survival, including Kaplan-Meier survival curves, indicates that vinyl chloride
decreased survival in a dose-dependent manner.
In the Maltoni experiments, exposure to vinyl chloride was associated with an increased incidence of
malignant tumors at a variety of tissue sites in all of the species tested. A summary of these tumor sites
is provided in Table 7 (Maltoni et al., 1984). A direct relationship between exposure levels and tumor
incidence was apparently demonstrated, although no statistical tests for trends were performed. Results
of experiments on Sprague-Dawley rats exposed to vinyl chloride for 52 weeks were statistically
analyzed using the Fischer exact probability test. A summary of the lowest concentrations at which a
statistically significant excess of tumors was observed is given in Table 8. When adjusted to average
lifetime exposure, the lowest concentration associated with tumor production is 0.06 ppm (1 ppm *
4/24 * 5/7 * 12/24 - 0.3 ppm).
Table 7: Tumors correlated to inhalation exposure to vinyl chloride in rats, mice, and hamsters in
the BT experiments (Maltoni et al., 1984).
Tumors Rat Mouse Hamster
Liver angiosarcomas + + +
Hepatomas + (+)
Encephalic neuroblastomas +
Lung adenomas +
Lymphomas/leukemias (+)
Angiosarcomas at other sites + + (+)
Zymbal gland epithelial tumors +
Nephroblastomas +
Cutaneous epithelial tumors (+) (+) (+)
Mammary adenocarcinomas + +
Forestomach papillomas, acanthomas + (+) +
+ Tumor incidence was statistically significant (p < 0.05) by the Fisher exact test.
(+) Association was not statistically significant, but was considered biologically significant.
Table 8:
Tumor type
forestomach papilloma
Zymbal gland carcinoma
neuroblastoma
nephroblastoma
liver angiosarcoma
mammary adenocarcinoma
Lowest concentration of VC at which a significant incidence of tumors (p < 0.05) was
reported by Maltoni et al. (1984) at specific sites in Sprague-Dawley rats.
Vinyl chloride concentration (ppm)
30,000 (male, female)
10,000 (male, female)
10,000 (female)
250 (female)
200 (male); 25 (female)
1 (female)
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