The International Agency for Research on Cancer classifies Trichloroethylene (TCE) as probably carcinogenic to humans (Group 2A). Here's a direct link to IARC's summary and evaluation (Updated 1997).



Update: The direct link above is no longer active. Try here.

Direct link here. Also added as permanent link in the right column under Science/Agency sites (------>)

Update:

ATSDR's full Toxicological profile of TCE (1997) is here.

Since approximately 1993, the ATSDR has been tracking the health effects reported by discreet communities exposed to Trichloroethylene. Their National Exposure Registry (NER) basically tracks this kind of data for well-identified communities who have been exposed to it (there are myriad qualification requirements, I'm simplifying here).

The NER for TCE has some interesting data and discussion. It raises questions about elevated cancer findings among the TCE-exposed population. Unfortunately, the detailed comparison of cancer types by age/sex for the exposed population vs. the general population never actually appears in the reports (despite references to appendices with this data in 3 separate reporting years: 1994, 1996, and 1999). Maybe I just can't find it. To be sure, in May of 2004, I wrote the ATSDR to request the missing data/appendices. I received this response:

Mr. Fischbein:

The TCE Subregistry cancer outcomes analyses are slated to be released under a separate study. The results are not publically available at this time. Please do keep tabs on our publications for future releases.

I confess, I'm not sure what to make of this. If anybody has any thoughts, please let me know or feel free to use the comments feature below.

In the U.S. National Toxicology Program's 11th Report on Carcinogens, TCE is reasonably anticipated to be a human carcinogen.

Here's a pdf of the TCE review only. Thanks to VJ for link.

In 2002, the EPA's Science Advisory Board (SAB) reviewed the EPA's 2001 draft health assessment of TCE. The SAB "commends the [EPA] for its groundbreaking work [...] in several important new areas of risk assessment" while also providing suggestions "to strengthen and provide confidence in the assessment."

Here is the full SAB review. Thanks to reader VJ for the link.

Here's a direct link to the EPA's 2001 Document: Trichloroethylene Health Risk Assessment: Synthesis and Characterization (external review draft)

From the EPA's abstract:

This assessment presents EPA's most current evaluation of the potential health risks from exposure to trichloroethylene (TCE). TCE exposure is associated with several adverse health effects, including neurotoxicity, immunotoxicity, developmental toxicity, liver toxicity, kidney toxicity, endocrine effects, and several forms of cancer. Mechanistic research indicates that TCE-induced carcinogenesis is complex, involving multiple carcinogenic metabolites acting through multiple modes of action. Under EPA's proposed (1996, 1999) cancer guidelines, TCE can be characterized as "highly likely to produce cancer in humans."

Update:

I'm trying to find the published responses to this document. I know the Halogenated Solvents Industry (along with several others, if I recall correctly) filed a rather lengthy response. If anyone knows where I can find these, please email me.