CAREX Canada

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CAS No. 79-01-6

Photo: Wikimedia Commons Photo^[1]

IARC Monograph Vol. 63, 1995 (Group 2A)

General Information

Trichloroethylene is a clear liquid at room temperature with a sweet, chloroform-like odour.^[2] Produced commercially since the 1920s, trichloroethylene has been used as a solvent and degreaser.^[3] Trichloroethylene is related to another chlorinated solvent, tetrachloroethylene (also called perchloroethylene or PERC). See the CAREX Carcinogen Profile for Tetrachloroethylene for more information. Trichloroethylene may also be referred to as trichloroethene or TCE.^[2] There are numerous other synonyms and product names; see HSDB for more information.^[4]

Trichloroethylene has been classified by IARC as Group 2A, probably carcinogenic to humans, based on sufficient evidence from experimental animal studies and limited evidence from human studies.^[3] The most relevant human studies do show consistent evidence of a link with liver and biliary tract cancer as well as modestly elevated rates of non-Hodgkin’s lymphoma, but the studies were limited because exposures to other solvents could not always be adequately controlled for.^[3]

Additional adverse health effects associated with low to moderate inhalation exposure to trichloroethylene range from headaches and dizziness to nerve damage.^[2] Acute exposures may cause damage to the kidneys and liver and arrhythmias.^[2] Skin irritation following dermal exposure has also been reported.^[2]

Trichloroethylene has been ranked by CAREX Canada as Group A (immediate high priority) for occupational settings and as Group B (possible high priority) for environmental settings. Prioritization was based on the carcinogenicity and other toxic properties of the substance, the prevalence of exposure in Canada, and the feasibility of assessing exposure.

Regulations and Guidelines

Occupational Exposure Limits (OEL)

Canadian Jurisdictions	OEL (ppm)
Canada Labour Code	10 25 [stel]
BC, MB, ON, NL, PE, NB, NS	10 25 [stel]
AB, SK	50 100 [stel]
QC	50 200 [stel]
NT, NU, YT	100 150 [stel]
Other Jurisdiction	OEL (ppm)
ACGIH 2011 TLV	10 25 [stel]

ppm = parts per million

stel = short term exposure limit (15 min. maximum)

Canadian Environmental Guidelines

Jurisdiction	Limit	Year
Canadian Drinking Water Guidelines	0.005	2010^[6]

Trichloroethylene was not included in other Canadian government environmental guidelines reviewed.^[7,14,15]

Canadian Agencies/Organizations

Agency	Designation/Position	Year
Health Canada	DSL – low priority substance (already risk managed)	2006^[8]
CEPA	Schedule 1, paragraphs ‘a’ and ‘c’ (human health)	1999^[9]
CEPA 1999: Solvent Degreasing Regulations	Users of >1,000 kg.yr of PERC or TCE for cold or vapour degreasing must comply with these regulations	2003^[10]

Trichloroethylene was not included in other Canadian government chemical listings reviewed.^[16]

Main Uses

Trichloroethylene is used primarily for the degreasing of metals in the automotive and metal industries.^[11] In 1995, the degreasing of metals accounted for 80-90% of trichloroethylene use worldwide.^[3] Other uses include the production of adhesives and copolymers, the cleaning of electronic components, petroleum industry processes involving refining catalysts, paint removers, coatings and vinyl resins, and in laboratory reagent/solvent applications.^[12]

Trichloroethylene has been used in the past as a solvent to extract natural fats and oils, spices, hops, and caffeine from food products.^[5] It has also been used as a dry cleaning solvent, but since the 1950s this use has been very limited.^[3] Use as a spot treatment in the textile industry, however, continued into the 1990’s at least.^[13]

Canadian Production and Trade

Production and Trade

Activity	Quantity	Year
Canadian Production	N/A [Ceased in 1985]	1993^[11]
Domestic Consumption	2,600 t	2004 (forecasted)^[12]
Export: Mainly to Kyrgyzstan	4 t of ‘trichloroethylene’	2010^[17]
Import: Partner(s) not specified	1 t of ‘trichloroethylene’	2010^[17]

t = tonne

Occupational Exposures

Inhalation is the most important route of occupational exposure to trichloroethylene.^[3] Workers involved in the degreasing of metals are the most heavily exposed occupational group.^[3]

The main industrial groups that use trichloroethylene for degreasing purposes are manufacturers of furniture and fixtures, fabricated metal products, electrical and electronic equipment, and transport equipment.^[5]

Environmental Exposures

The primary route of exposure to the general public is inhalation of indoor air.^[5,11] Minor sources of exposure include food, drinking water, and outdoor air.^[11] TCE in indoor air likely comes from volatilization from water sources (i.e. during showering), as well as from household products containing the solvent.^[2]

Recent surveys of levels of TCE in food products in Canada are not available, but trichloroethylene has not been allowed in the preparation of foodstuffs since 1977.^[11] Older studies have found TCE in a variety of foods including dairy products, meats, oils and fats, beverages, fruits and vegetables. Margarine was found to contain the highest levels of trichloroethylene (440 to 3,600 ppb).^[2]

Environment and Health Canada estimated that the average Canadian’s daily intake of trichloroethylene is in the range of 0.37 - 0.60 mg/kg of body weight per day.^[11] Most trichloroethylene that is used is expected to eventually enter the atmosphere.^[11]

Point sources which may cause higher localized environmental levels of TCE include metal degreasing operations, sewage treatment plants, textile mills, landfills, incinerators, and septic tanks.^[11]

Trichloroethylene can be formed in groundwater by the breakdown of tetrachloroethylene.^[11]

Searches of environmental and consumer product databases yielded the following results on current potential for exposure to trichloroethylene in Canada:

NPRI and US Household Products Database

NPRI 2009^[18]
Search term: ‘trichloroethylene'
Category	Quantity	Industry
Released into Environment	146 t	Aerospace plastics, iron and steel pipe manufacture, chemical and glue manufacture (49 companies)
Disposed of	54 t
Sent to off-site recycling	113 t

US Household Products 2010^[19]
Search Term	Quantity	Product Type
'trichloroethylene'	12	Cleaners/degreasers, vehicle undercoating, adhesives, cleaners, sealants (hobby use), and toner enhancer