Vinyl Chloride Monomer (VCM)
VCM is used to make polyvinyl chloride (PVC). PVC is used to make a variety of products, including plastics, hoses, pipes and fittings for outdoor irrigation, wire and cable coatings, packaging materials, furniture and automobile upholstery, flooring, windows, credit or ATM cards, wall coverings, housewares, outdoor furniture, plastic containers, wrapping film, automotive parts and many others. In the past VCM has been used as a refrigerant.
Substance name: Vinyl chloride monomer
CASR number: 75-01-4
Molecular formula: C2H3Cl
Synonyms: vinyl chloride, VC, VCM, chloroethylene, chloroethene, ethylene monochloride, monochloroethylene, monochloroethene.
VCM is a colourless gas, it is extremely flammable and unstable. It has a mild, sweet odour. The threshold for detecting odour is 3000 parts per million. VCM is soluble in many organic solvents but is not soluble in water. VCM is considered a volatile organic compound by the National Pollutant Inventory.
Specific gravity: 0.9106
Melting Point: -153.8
Boiling Point: -13.4
Relative vapour density: 2.2
Flash point: -77.8
VCM can polymerise rapidly due to heating and under the influence of air, light and contact with a catalyst, strong oxidisers and metals such as copper and aluminium, with fire or explosion hazard. As a gas mixed with air, VCM is a fire and explosion hazard. On standing VCM can form peroxides, which may then explode. VCM will react with iron and steel in the presence of moisture.
The National Pollutant Inventory (NPI) holds data for all sources of Vinyl Chloride Monomer in Australia.
Breathing high concentrations of VCM fumes for a short time may cause headaches, dizziness, sleepiness, unconsciousness, and at extremely high levels, can lead to death. Breathing VCM fumes over a long period of time (many years) can result in impotence, permanent liver damage, immunological dysfunction and nerve damage.
If VCM is spilt on the skin, it will cause numbness, redness and blisters and will cause symptoms similar to frostbite.
The Office of the Australian Safety and Compensation Council has classified VCM as a human carcinogen, a substance capable of causing cancer. This is based on evidence of carcinogenicity in humans and animals.
Entering the body
VCM can enter the body by inhaling fumes or by contact with eyes and skin. For most people, exposure is not likely and the only real risk is to those who work with VCM.
The most likely exposure to VCM will occur in a workplace that uses this substance, by breathing contaminated air, or by contact with the eyes or skin. Exposure can also occur by breathing VCM released from hazardous waste sites, landfills, or by drinking water from contaminated bodies of water. Although such a situation is possible, it is not considered likely.
If you think you have been exposed to VCM, seek medical help immediately.
Currently, the eight-hour time weighted average (TWA) exposure limit is 13 milligrams VCM per cubic metre of air. A 15-minute short term exposure limit (STEL) has not been recommended.
Australian Drinking Water Guidelines:
In 2004, the National Health and Medical Research Council (NHMRC) and National Resource Management Ministerial Council (NRMMC) established that no safe concentration level can be confidently set for VCM, however the concentration should be less than 0.0003 milligrams per litre of water, the limit of scientific determination for this substance.
VCM enters the air during production and use. If VCM is present in the air, it breaks down to other substances within 2-3 days. Similarly, VCM will quickly evaporate if released to surface water. Some small amounts of VCM may be released to soil where it will either evaporate or leach into the ground water, where it may persist for months to years. There is insufficient information to predict the toxicity of VCM to aquatic life, plants, birds or animals. VCM is unlikely to bio-accumulate in plants or animals.
Entering the environment
VCM does not occur natually. If VCM is present in the environment, it is from being used in production or as a result of pollution caused by chemical spills. It has not been found in Australian drinking water, however the standard established (as listed previously) is to provide guidance in the unlikely event of contamination.
Where it ends up
Liquid VCM evaporates easily. If VCM is present in the water or soil, it will evaporate rapidly if it is near the surface.
Currently, there are no Australian environmental guidelines for VCM.
Industries that manufacture or use VCM in production are the primary sources of this substance. Some of these industries include the chemical industry (for the manufacture of PVC and other chemicals) and the plastics industry. Emissions or VCM are primarily to air, with a small percentage to water.
Diffuse sources and industry sources included in diffuse emissions data
Landfills which contain VCM or other chlorinated hydrocarbons will release VCM. The treatment of wastewater containing vinyl chloride or chlorinated hydrocarbons may release VCM.
VCM does not form naturally in the environment.
There are no sources of VCM that arise from transport.
Many consumer products are made from or contain PVC. New PVC products may have trace amounts of VCM seep from new plastic parts.
The agreed Australian standard for the resin is for less than 1 part of VCM per million parts of PVC.
Sources used in preparing this information
- Agency for Toxic Substances and Disease Registry (ASTDR), ToxFAQS: Vinyl Chloride, accessed February 2007.
- Merck and Co. 2001, Merck Index, 13th Edition, USA.
- National Health and Medical Research Council (NHMRC) and National Resource Management Ministerial Council (NRMMC) (2004), Australian Drinking Water Guidelines 6, accessed February 2007.
- National Pollutant Inventory (1999): Contextual Information.
- Office of the Australian Safety and Compensation Council, Exposure Standards: Vinyl chloride, monomer, accessed February 2007.
- Technical Advisory Panel 1999, Final Report to the National Environment Protection Council.
- United Nations, International Chemical Safety Cards: Chloroethene, accessed February 2007.
- US Environmental Protection Agency, Technology Transfer Network Air Toxics Website: Vinyl chloride, accessed February 2007.