On September 28, 2011, the United States Environmental Protection Agency (EPA) listed trichloroethylene (TCE) in the EPA Integrated Risk Information System database as carcinogenic to humans. While this task, in and of itself, is a simple one, the procedural history, background, and basis for this action and any effect it may have is not. The significance, effect, and use of this classification will be debated by lawyers and decided by judges and appellate courts in the years to come, but there should be no confusion that this agency action is a classification based on estimated risk and purpose, not a pronouncement of a presumption on proximate cause. Given the historical use of TCE in industry in the United States and the presence of TCE in the environment in various parts of the United States, the debate regarding causation of disease and the likelihood to cause future disease has been continuing for years.
The federal and state governments regulate hazardous substances through many different agencies, such as the EPA, the Occupational Safety and Health Administration (OSHA), and many other agencies. Local authorities may regulate independently or in conjunction with federal law. Further, the same agent may have different regulated levels in different contexts. This recent EPA classification, not unlike other past actions by regulatory agencies, will surely fan the flames of the debate with regard exposure to TCE and the causation of alleged disease in tort claims. Forthcoming debate in that regard should prompt us to keep in mind what an administrative classification is and is not. When faced with an attempt to use an agency ruling on the carcinogenesis of an agent as a basis of an opinion on causation or to bolster or support such an opinion, one must thoroughly understand the risk assessment methodology used in formulating any regulatory levels, as well as the bases of the toxicity data. To do that, we need to be sure we understand the process by which such an agency classification is reached and the stark contrasts between the purposes and bases of a regulatory administrative action and reliability and admissibility in a court of law. A full discussion of these issues is beyond the scope of this article. However, the following is a brief examination of some of the relevant points of discussion.