Science and transscience in carcinogen risk assessment--the European Union regulatory process for trichloroethylene

This is a study of carcinogen risk assessment of the chlorinated solvent trichloroethylene within the European Union existing substances program and the classification and labeling process. The focus is on the most active and influential participants of this process, namely, those from the United Kingdom, Germany, and Sweden, and from industry. The member state and other experts have different opinions regarding the appropriate classification of trichloroethylene for mutagenicity (no classification or category 3) and carcinogenicity (category 3, 2, or 1). In this article these differences are described, as well as how the primary carcinogenicity and mutagenicity data have been interpreted and evaluated by these participants. It is concluded that underlying the different assessments are disagreements about issues that to some degree lie outside the scope of purely scientific considerations.