Trichloroethylene

In 1996, trichloroethylene was classified in Carcinogen category 1 in the List of MAK and BAT Values. This classification was considered necessary because the substance had been shown to cause renal cancer in exposed workers. Renal tumours also developed in studies with rats (see “Trichloroethylene”, Volume 10, present series). As described in the 1996 documentation, genotoxic effects together with the renal toxicity caused by high level exposure play a role in the development of the kidney tumours. Thus the requirements for reclassification of the substance in Category 5 would be fulfilled provided that data appropriate for the derivation of a MAK value were available. Therefore, in the text which follows, the important studies of effects on the CNS, renal toxicity, renal carcinogenicity and critical mechanisms, and the data for doseresponse relationships are presented. The classification of the substance for its mutagenic effects on germ cells is also documented.