|Occupational Health and Safety
Hazardous Substances: Trichloroethylene
Some Trade Names
Tir, Trichlor, Trilene, Ethylene Trichloride, Trichloran
Applications and Use
Trichloroethylene is a widely used solvent. It is found in degreasing operations, metal cleaning operations, and in some varnishes
Colourless liquid or vapour with a sweetish odour. Its vapours are heavier than air and may accumulate. It is non-flammable under
Trichloroethylene exposure can have both short-term and long-term ill-health effects. Exposure results from inhaling the vapour,
contact and absorption through the skin, and ingestion.
Short-term Ill-Health Effects
Regular contact with the skin may cause dermatitis as the chemical dissolves the oily protective substances in the skin. Look for
signs of skin reddening, drying, and breaks. Secondary infection may occur once the dermatitis has developed.
Splashing of the chemical and exposure to the vapour may also cause irritation of the eyes, nose and throat.
The health effects from inhalation of the vapours and absorption through the skin are similar. The chemical depresses the central
nervous system and exposures may produce headaches, dizziness, nausea, lightheadedness, blurred vision, tremors. The chemical
also affects the heart and can produce irregular heart beat, heart racing and cardiac arrest.
Long-term Ill Effects
Longer-term (chronic) exposures to low levels of the chemical (under 100 parts per million) can cause a number of ill health
complaints. These include: headaches, drowsiness, anxiety, depression, intolerance to alcohol, nerve damage. Nerve damage may
appear in the arms, hands, and legs.
There is some evidence that liver and kidney damage can result from exposures. Extensive damage has been observed in animals
tests, and some reports from human exposures have been documented. Due to lack of proper medical surveillance, the full extent of
liver and kidney problems resulting from exposure is not known.
Cancer and Reproductive Effects
In 1976 animal tests confirmed that exposure to trichloroethylene can result in cancer of the liver. Other non-human experiments
have shown the chemical to be capable of causing cell mutation. On this basis health authorities such as the U.S. National Cancer
Institute and the National Institute of Occupational Health and Safety in the United States have concluded that trichloroethylene
should be regarded as a potential human carcinogen. The chemical may also be transformed in the body to produce other cancer-
It is also known that this chemical can rapidly cross the placenta of pregnant women and may affect the unborn offspring.
Miscarriages or birth abnormalities may result if pregnant women are regularly exposed to this chemical.
ACGIH TLV 50 ppm (269 mg/m3).
U.S. NIOSH recommendation: 25 ppm to be reduced to less than 1 ppm.
Other limits are as low as 2 ppm.
Ill health effects have been observed among workers exposed to levels of this chemical as low as 10 ppm. The current standard
was not set in order to eliminate the risks of cancer or birth abnormalities. On this basis, it has been strongly recommended that all
exposures to this chemical be reduced to the lowest levels technically possible. This can be done by proper use of engineering
- All Containers of trichloroethylene should be labeled, contents clearly identified and a HEALTH HAZARD! WARNING POSTED.
- Do not store or use the chemical around high temperature sources, and welding or cutting operations. On contact with hot
metal or with welding operations phosgene or “combat gas” can evolve. Serious lung damage can result on esposure.
- All degreaser operations must be covered and exhaust ventilation supplied. Full enclosures for open degreasers are strongly
recommended. These controls can reduce air levels of vapour to less than 10ppm. A drainage area for parts should be
The best protection is to reduce contamination at source. Where worker contact is unavoidable, and as a short term emergency
measure, proper personal protective equipment must be used:
- chemical cartridge respirators with an organic vapour cartridge
- supplied air respirator with a full face piece for exposures over 500 ppm
- protective clothing (impervious to the chemical)
- eye goggles
Remove wet clothing that is not impervious immediately. Wash the affected area with soap and water.
All areas where this chemical is used should be regularly monitored. It is important to know how much exposure is occurring both in
order to eliminate it and to record all exposures workers have suffered.
In-plant monitoring programs should be implemented so that regular shift by shift changes in conditions can be known. Three
methods of monitoring are:.
- Survey Meters specific for trichloroethylene
- Air sampling with charcoal tubes and a personal pump - sent to a laboratory for analysis.
- Draeger or MSA indicator tubes.
In all areas where workers have health complaints due to exposure the more accurate methods should be used. These include
survey meters and the collection of samples on charcoal tubes.
A Final Word
Trichloroethylene is a potentially dangerous chemical. All exposed workers are at risk. Those with heart conditions, and pregnant
workers are at special risk. Engineering controls are available that can reduce the exposures to practically zero. It is your right and
responsibility to demand they be implemented.
1. Inform all exposed workers of the hazards of trichloroethylene
2. Record all health complaints
3. Insist the plant be monitored
4. Work with your Union Health and Safety Committee towards eliminating this serious health hazard.
Source: CAW Health, Safety & Environment Department