US EPA

These issue papers are a part of EPA's effort to develop a trichloroethylene (TCE) human health risk assessment. These issue papers were developed by EPA to provide scientific and technical information to the National Academy of Sciences (NAS) for use in developing their advice on how to best address the important scientific issues surrounding TCE health risks. As such, these papers discuss a wide range of perspectives and scientific information (current through Fall 2004) on some of these important issues, highlighting areas of continuing uncertainty and data that may be relevant. They are intended to be useful characterizations of the issues, not a presentation of EPA conclusions on the issues.

Background:

ORDs National Center for Environmental Assessment is preparing a human health risk assessment on trichloroethylene (TCE). TCE is a solvent that has been widely used for vapor degreasing of metal parts, as an ingredient in adhesives, paint removers, correction fluid and spot removers, and as an extractant and chemical intermediate. Subsequent to its release, EPA's 2001 draft health risk assessment of TCE underwent a peer review by a panel of independent scientists through EPA's Science Advisory Board (SAB), which provided a peer review report in December 2002. In addition, the public submitted more than 800 pages of comments to EPA during a 120-day public comment period. Due to continuing science issues as well as emerging significant new science, further revision and external review have been planned. EPA, along with the Department of Defense, Department of Energy, and the National Aeronautics and Space Administration, is cosponsoring a consultation on TCE science issues with an expert panel convened by the NAS Board on Environmental Studies and Toxicology. EPA has developed four issue papers that highlight important scientific issues related to TCE. These papers were provided to the NAS on February 15, 2005.

The documents and their respective EPA numbers are as follows (view documents):

• TCE Issue Paper 1: Issues in Trichloroethylene Pharmacokinetics - EPA/600/R-05/022, 2005.
• TCE Issue Paper 2: Interactions of Trichloroethylene, Its Metabolites, and Other Chemical Exposures - EPA/600/R-05/023, 2005.
• TCE Issue Paper 3: Role of Peroxisome Proliferator-Activated Receptor Agonism and Cell Signaling in Trichloroethylene Toxicity - EPA/600/R-05/024, 2005.
• TCE Issue Paper 4: Issues in Trichloroethylene Cancer Epidemiology - EPA/600/R-05/025, 2005.

TCE Health Risk Assessment Chronology:

• August 2001: External review draft Trichloroethylene Health Risk Assessment: Synthesis and Characterization released.
• December 2002: EPA Science Advisory Board independent peer review report Review of Draft Trichloroethylene Health Risk Assessment: Synthesis and Characterization: An EPA Science Advisory Board Report (PDF, 83 pp, 376 KB, about PDF) published.
• February 2004: Symposium on New Scientific Research Related to the Health Effects of Trichloroethylene held in Washington, DC.
• September 2004: National Academy of Science consultation Trichloroethylene Health Risks: Key Scientific Issues initiated under sponsorship of EPA and other federal agencies.

Next Steps:

Meetings of the NAS expert panel held March 23-24 and then April 20-21, 2005. A report from the NAS is expected in 2006. The concepts presented in EPA's issue papers will eventually be addressed in EPA's revised risk assessment of TCE, after the advice from the NAS, along with comments from the EPA Science Advisory Board and the public, as well as recently published scientific literature, have been incorporated. The revised TCE risk assessment will then undergo both external peer review and public comment.

U.S. EPA. TRICHLOROETHYLENE (TCE) ISSUE PAPERS. EPA/600/R-05/022, 2005.