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CAS No. 75-01-4

Photo: Wikimedia Commons, 2007^[1]

IARC Monograph Vol. 97, 2008 (Group 1)

General Information

Vinyl chloride is a chlorinated aliphatic hydrocarbon which occurs as a colourless gas. It has a light sweet odour and is slightly soluble in water.^[2] It may also be referred to as vinyl chloride monomer, chloroethene, ethylene mono-chloride, or mono-chloroethylene.^[3] There are numerous other synonyms and product names; see HSDB for more information.^[3]

Vinyl chloride is classified by IARC as a group 1 agent, carcinogenic to humans. There is sufficient evidence that vinyl chloride exposure causes angiosarcoma of the liver and hepatocellular carcinoma.^[4] Epidemiological evidence also suggests a possible association between vinyl chloride exposure and the development of malignant neoplasms of connective and soft tissue.^[4]

Acute inhalation exposure to vinyl chloride can cause dizziness, nausea, headache, fatigue, visual and hearing disturbances, sleep disturbances, unconsciousness, and in high concentrations, death.^[5,6] Chronic exposure to vinyl chloride is associated with a number of non-cancer health effects in different organs and tissues, including the liver, skin, and bones, as well as the cardiovascular, nervous, immune and reproductive systems.^[5,6]

Vinyl chloride has been ranked by CAREX Canada as Group B (possible high priority) for both the occupational and 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	1
AB, BC, MB, NB, NL, NS, ON, PE, YT	1
SK	None listed*
QC	1 5 [stel]
NT, NU	2 10 [stel]
Other Jurisdictions	OEL (ppm)
ACGIH 2010 TLV	1

*Written notice to Ministry of Labour Relations and Workplace Safety required for use and disposal.

ppm = parts per million

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

TLV = Threshold Limit Value (8 hour maximum)

Canadian Environmental Guidelines

Jurisdiction	Limit	Year
Canadian Drinking Water Guidelines	0.002 mg/L (MAC)	2010^[7]
Residential Indoor Air Quality	Recommended that any exposure to tobacco smoke* in indoor environments be avoided	1987^[8]
Health Canada Cosmetics Ingredient Hotlist	Not permitted	2010^[9]

*Vinyl chloride included under ‘Tobacco Smoke.’

MAC = Maximum Acceptable Concentration

Vinyl chloride was not included in Health Canada's List of Food Additives Permitted for Use in Canada^[10].

Canadian Agencies/Organizations

Agency	Designation/Position	Year
Health Canada	DSL – low priority substance (already risk managed)	2006^[11]
CEPA	Schedule 1, paragraph 'c' (human health)	1999^[12]
Environment Canada	Vinyl chloride release regulations: limit the release of vinyl chloride from vinyl chloride plants and polyvinyl chloride plants	1992^[13]

Vinyl chloride was not included in the Government of Canada's Chemicals Management Plan^[14].

Main Uses

Approximately 98% of vinyl chloride monomer produced is used for polyvinyl chloride (PVC) production.^{[2, 5]} PVC is an important plastic used in a variety of products, including automotive parts, pipes, medical supplies, packaging products, furniture, and construction materials.^{[2, 5]}

Other minor uses for vinyl chloride include the organic synthesis of copolymers with vinyl acetate, vinyl stearate and vinylidene chloride and 1,1,1-trichloroethane.^[5]

Vinyl chloride was formerly used as a refrigerant and in aerosol propellants, as an extraction solvent and as an ingredient in pharmaceutical and cosmetic products.^[3] These uses were discontinued in the 1970s following the recognition of the carcinogenicity of vinyl chloride.^{[2, 5]}

Canadian Production & Trade

Historically, two chemical manufacturing plants, both operated by Dow Chemical, produced vinyl chloride monomer in Canada. The Sarnia, ON plant ceased vinyl chloride production in 1993 and the Fort Saskatchewan AB plant ceased production in 2006.^{[15, 16]}

Many PVC production plants in Canada have ceased production following the closure of domestic vinyl chloride production plants. These include BF Goodrich’s plant in Shawinigan, QC (closed in 1993),^[17] Oxy’s plant in Fort Saskatchewan, AB (closed 2006),^[18] and Royal Polymer’s plant in Sarnia, ON (closed in 2009).^[19] One operational Oxy PVC production plant remains in Niagara Falls, ON.^[17]

Currently, Canadian demand for vinyl chloride is met with imports, mainly from the US.^[20]

Production and Trade

Activity	Quantity	Year
Vinyl Chloride Canadian Production	550,000 t	2003^[15]
Vinyl Chloride Domestic Demand	533,000 t	2003^[15]
Vinyl Chloride Export: Mainly to the US	12,873 t	2006*^[20]
Vinyl Chloride Import: Mainly from the US	178,334 t	2010^[20]
Polyvinyl Chloride: Canadian Production	637,000 t	2006 (forecast)^[17]
Polyvinyl Chloride: Domestic Demand	727,000 t	2006 (forecast)^[17]

*2006 was the last year of significant domestic production of vinyl chloride in Canada.

t = tonne

Occupational Exposures

Inhalation is the most common route of occupational exposure to vinyl chloride, although skin absorption may also occur.^{[4, 5]}

The main occupations exposed include workers involved in vinyl chloride monomer production and use of vinyl chloride during PVC and other chemical production.^[2]

In vinyl chloride monomer production plants, exposures generally occur after production, when the monomer product is being transported and stored, or during equipment maintenance.^[2]

Exposure may occur during PVC polymerization or synthesis of other chemicals, if vinyl chloride is released into the air.^[2]

Workers involved in PVC resin handling and processing may be exposed to residual vinyl chloride monomers, but the levels of exposure are usually very low.^{[4, 5]}

North American and Western European countries introduced new occupational exposure limits for vinyl chloride in the 1970s, after recognizing the chemical’s carcinogenic effects.^{[4, 5]} By the late 1970s, many PVC manufacturers in these countries adopted the use of “closed-loop" polymerizing systems, which substantially reduced occupational exposure to vinyl chloride.^{[4, 5]}

CAREX Canada will not be preparing exposure estimates for Canadian workers exposed to vinyl chloride, based on the carcinogenicity and other toxic properties of the substance, the prevalence of exposure in Canada, and/or the feasibility of assessing exposure.

Environmental Exposures

Potential sources of environmental exposure to vinyl chloride include inhalation of contaminated air, ingestion of contaminated drinking water and foods, and use of PVC consumer products.^[2] Overall, exposure levels are expected to be very low in the general population.^[2]

Vinyl chloride is released into the environment from vinyl chloride and PVC manufacturers.^[4] Higher air concentrations of vinyl chloride have been found in communities located within close proximity to these sites.^[2,5] Air monitoring performed in Alberta from 1979 to 1984 near a vinyl chloride manufacturing plant found that concentrations of vinyl chloride in air ranged from 12.9 µg/m³ to 77.4 µg/m³.^[21] Recent air monitoring performed in Alberta found that the average vinyl chloride concentration was 2.46 µg/m³ near an operational PVC plant and 0.01 µg/m³ in the same area after the plant had ceased production.^[18] Levels of vinyl chloride in areas away from emission sources are generally very low.^{[2, 4]}

Contamination of drinking water may be caused by industrial release of the chemical or leaching of vinyl chloride monomers in PVC piping.^[21] A 1979 survey conducted at 30 Canadian water treatment plants found four water samples containing <1 µg/L of vinyl chloride.^[21] One study found that drinking water passing through new PVC pipes contained 1.4 µg/L of vinyl chloride whereas water that passed through nine-year-old pipes had 0.03-0.06 µg/L of vinyl chloride.^[21] Vinyl chloride exposure through ingestion of drinking water is not expected to occur for the majority of the general population.^{[2, 5]}

Regulations in Canada prohibit the leaching of vinyl chloride in food packaging.^[21] Exposure to vinyl chloride from food and beverage consumption is estimated to be around 0.1 µg/day.^[21]

PVC consumer products may contain residual amounts of vinyl chloride.^[4] Residual vinyl chloride concentrations > 0.13 mg/m³ (0.05 ppm) were found in products such as vinyl music records, plastic food bottles, kitchen wrapping films and bathroom tiles in the 1970s.^[4] Improved manufacturing processes in recent years have substantially reduced the levels of residual vinyl chloride in PVC products.^[4]

Vinyl chloride is found in the smoke of cigarettes (1.3-16 ng/cigarette), cigars (14-27 ng/cigar) and marijuana cigarettes (5.4 ng/cigarette).^{[2, 4]}

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

NPRI and US Household Products Database

NPRI 2006^[22]
Search Term:	'Vinyl Chloride'
Result:	7 companies

Category	Quantity	Industry
Released into Environment	1.3 t	PVC and chemical manufacturers
Disposed of	0.181 t
Sent to off-site recycling	0 t
US Household Products 2010^[23]
Results: 28 products
Search Term	Quantity	Product Type
'vinyl chloride'	0	-
'polyvinyl chloride'	28	Plumbing and pipe cements