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International Agency for Research on Cancer (IARC) - Summaries & Evaluations

VINYL CHLORIDE, POLYVINYL CHLORIDE AND
VINYL CHLORIDE-VINYL ACETATE COPOLYMERS

VOL.: 19 (1979) (p. 377)

Vinyl chloride
CAS No.: 75-01-4
Chem. Abstr. Name: Chloroethene

Polyvinyl chloride
CAS No.: 9002-86-2
Chem. Abstr. Name: Chloroethene homopolymer

Vinyl Chloride-vinyl acetate copolymers
CAS No.: 9003-22-9
Chem. Abstr. Name: Acetic acid ethenyl ester polymer with chloroethene

5. Summary of Data Reported and Evaluation

5.1 Experimental data

Vinyl chloride was tested in rats by oral, subcutaneous and intraperitoneal administration and in mice, rats and hamsters by inhalation exposure. Following oral and inhalation exposure, vinyl chloride was carcinogenic in all three species, producing tumours at different sites, including angiosarcomas of the liver. Vinyl chloride was carcinogenic in rats following prenatal exposure. A dose-response effect has been demonstrated.

The results of subcutaneous and intraperitoneal injection studies in rats are incomplete and cannot be evaluated.

Vinyl chloride is mutagenic.

Polyvinyl chloride was tested in rats by subcutaneous and intraperitoneal implantation; local sarcomas were induced, the incidence of which varied with the size and form of the implant.

Vinyl chloride-vinyl acetate copolymers were tested in mice by subcutaneous implantation as films or powder; local sarcomas were induced following implantation of films.

5.2 Human data

Vinyl chloride is manufactured on a vast scale, and exposure involves workers in the production, polymerization and processing industries. Also, large sections of the general population may have some exposure to vinyl chloride, particularly through direct or indirect contact with polymer products.

Several independent but mutually confirmatory studies have shown that exposure to vinyl chloride results in an increased carcinogenic risk in humans, involving the liver, brain, lung and haemo-lymphopoietic system.

In one epidemiological study, an excess of foetal mortality was reported among wives of workers who had been exposed to vinyl chloride, indicating a possible mutagenic effect in human germ cells. Several investigations have detected an increase in chromosomal aberrations in the lymphocytes of workers exposed to vinyl chloride. Increased rates of birth defects among children of parents residing in communities where vinyl chloride-polyvinyl chloride or other chemical processing plants are located have been reported in several other studies. These suggest teratogenic and/or mutagenic effects of vinyl chloride in humans.

In two proportionate mortality studies, in which death certificates of workers who had been involved in the fabrication of plastics, including polyvinyl chloride, were analysed, there appeared to be an increased proportion of cancer of the digestive system in both sexes and possibly of the urinary system and of the breast in women.

5.3 Evaluation

Vinyl chloride is a human carcinogen. Its target organs are the liver, brain, lung and haemo-lymphopoietic system. Similar carcinogenic effects were first demonstrated in rats and were later confirmed in mice and hamsters. Although evidence of a carcinogenic effect of vinyl chloride in humans has come from groups occupationally exposed to high doses of vinyl chloride, there is no evidence that there is an exposure level below which no increased risk of cancer would occur in humans.

Epidemiological reports regarding clastogenic effects among vinyl chloride-exposed workers and a single study of increased foetal mortality among the wives of workers who had been exposed to vinyl chloride suggest that vinyl chloride could be mutagenic to humans. Additional support for this suggestion derives from experimental evidence of its mutagenicity.

Studies which indicate increased rates of birth defects among the children of parents residing in communities where vinyl chloride production and polymerization plants are located indicate the necessity for further investigation of the teratogenicity of vinyl chloride and its polymers in both animals and humans.

The available studies on polyvinyl chloride, which indicate an elevated proportion of digestive system cancer in male and female workers and possibly of cancers of the breast and urinary organs in female workers involved in the fabrication of plastics, including polyvinyl chloride, are insufficient to evaluate the carcinogenicity of this compound.

Previous evaluation: Vol. 7 (1974)

Subsequent evaluations: Suppl. 7 (1987) (Vinyl chloride) (Polyvinyl chloride, p. 70: Group 3) (Vinylidene chloride-vinyl chloride copolymers, p. 73: Group 3)

For definition of Groups, see Preamble Evaluation.

Synonyms for Vinyl chloride

Synonyms for Polyvinyl chloride

Synonyms for Vinyl chloride-vinyl acetate copolymers


Last updated: 30 March 1998






















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       Toxicological Abbreviations