The International Agency for Research on Cancer (IARC) has evaluated the carcinogenicity of a number of chlorinated agents, including trichloroethylene and tetrachloroethylene. Trichloroethylene and tetrachloroethylene have both been used in dry cleaning and as metal degreasers, among other uses. Trichloroethylene was classified as carcinogenic to humans (IARC Group 1), while tetrachloroethylene was classified as probably carcinogenic to humans (IARC Group 2A).
Click here for more information on how IARC classifies carcinogens.