The following paper was published back in April:

Occupational trichloroethylene exposure as a cause of idiosyncratic generalized skin disorders and accompanying hepatitis similar to drug hypersensitivities [View abstract or purchase]

Authors: Kamijima, Michihiro1; Hisanaga, Naomi; Wang, Hailan; Nakajima, Tamie
Source: International Archives of Occupational and Environmental Health, Volume 80, Number 5, April 2007 , pp. 357-370(14)
Publisher: Springer

After reading the abstract and the paper, we decided a layman's summary was warranted. Here's our attempt:

Researchers reviewed cases of severe generalized skin disorders and accompanying hepatitis in workers exposed to trichloroethylene (TCE). They attempted to compare TCE-induced skin disorders to similar disorders caused by hypersensitivity to medications.

Not only was the frequency of skin disorders in TCE-exposed workers greater than the occurrence of such disorders caused by medicine-hypersensitivity, the TCE-induced skin disorders were accompanied by a higher rate of fever, hepatitis, and lymphadenopathy (swelling of the lymph nodes). [Note: For several reasons, the incidence rate/frequency surveyed does not seem to offer much predictive power.]

Patients suffering from TCE-related generalized skin disorders typically show rash on the extremities, face, neck or trunk with/without fever 2 weeks to 2 months after commencement of occupational TCE exposure. Some experienced recurrences after going back to their worksites. These findings indicate a clear temporal relationship between TCE exposure and the disorder occurrence.

TCE-induced skin disorders found in the review include:

• Exfoliative Dermatitis (widespread scaling of the skin, often with itching (pruritus), skin redness (erythroderma), and hair loss.)
• Erythema Multiforme (multiple skin lesions; can be accompanied by itching, fever, and general ill-feeling)
• Stevens-Johnson syndrome (a much more severe condition than erythema multiforme. SJS typically involves multiple areas of the body and extensive lesion formation. The lesions can extend to the mucous membranes, thus affecting the lungs, eyes, mouth, stomach, intestines and virtually every major organ.)
• Epidermolysis Bullosa (a group of blistering skin conditions. The skin is so fragile in people with EB that even minor rubbing may cause blistering. At times, the person with EB may not be aware of rubbing or injuring the skin even though blisters develop. In severe EB, blisters are not confined to the outer skin. They may develop inside the body, in such places as the linings of the mouth, esophagus, stomach, intestines, upper airway, bladder, and the genitals.)

Also:

The reported patients were engaged mostly in degreasing, i.e. cleaning metal-made products or machines, plastic toys, electronics parts (e.g. printed circuit boards, transistor components, capacitors, or computer displays), socks, ink stains in a printing shop , or unspecied material.

Skin contact with liquid TCE is not essential for the onset of the disorders (i.e. TCE vapors can cause them)

These TCE-related hypersensitivities are totally different from typical solvent toxic effects in terms of unclear dose–response relationship, period of exposure before disease onset, generalized rash, fever, lymphadenopathy, and recurrence just after minimal re-exposure

Occurrences of the disorders have been reported from the USA, Japan, Spain, Singapore, China, Korea, Thailand, and the Philippines. The case reports from industrialized countries were mostly published up to 1990, whereas cases from Asian industrializing countries appeared thereafter.

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For a copy of the full paper for research purposes, please feel free to contact us.

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 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.