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

(Group 3)

For definition of Groups, see Preamble Evaluation.

VOL.: 71 (1999) (p. 1133)

CAS No.: 630-20-6
Chem. Abstr. Name: 1,1,1,2-Tetrachloroethane

5. Summary of Data Reported and Evaluation

5.1 Exposure data

1,1,1,2-Tetrachloroethane is an intermediate in one process for the manufacture of trichloroethylene and tetrachloroethylene and has been reported to occur as an impurity in these widely used products. It has been detected at low levels in ambient air and in drinking-water.

5.2 Human carcinogenicity data

No data were available to the Working Group.

5.3 Animal carcinogenicity data

1,1,1,2-Tetrachloroethane was tested for carcinogenicity by oral administration by gavage in one study in mice and one study in rats. An increased incidence of hepatocellular adenomas was observed in mice of each sex and of hepatocellular carcinomas in females. The experiment in male rats gave negative results and that in female rats was inconclusive. In one small experiment in rats, no initiating or promoting activity of 1,1,1,2-tetrachloroethane was demonstrated.

5.4 Other relevant data

In a single study, 1,1,1,2-tetrachloroethane bound covalently to DNA in rats and mice in vivo. It induced gene mutations, sister chromatid exchanges and aneuploidy, but not chromosomal aberrations, in rodent cell cultures. It did not induce sex-linked recessive mutation in Drosophila or mutations or aneuploidy in yeast. 1,1,1,2-Tetrachloroethane induced gene conversion in yeast, genetic crossing-over and aneuploidy in fungus and gene mutations in bacteria.

5.5 Evaluation

No epidemiological data relevant to the carcinogenicity of 1,1,1,2-tetrachloroethane were available.

There is limited evidence in experimental animals for the carcinogenicity of 1,1,1,2-tetrachloroethane.

Overall evaluation

1,1,1,2-Tetrachloroethane is not classifiable as to its carcinogenicity to humans (Group 3).

For definition of the italicized terms, see Preamble Evaluation.

Previous evaluations: Vol. 41 (1986); Suppl. 7 (1987)


Last updated: 13 April 1999

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