Vinyl Chloride Profile

Vinyl Chloride Profile

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.[1] It may also be referred to as vinyl chloride monomer or chloroethene.[2] There are numerous other synonyms and product names; see the Hazardous Substances Data Bank (HSDB) for more information.[2]

Vinyl chloride is classified by the International Agency for Research on Cancer (IARC) as Group 1, a known human carcinogen. There is sufficient evidence that vinyl chloride exposure causes angiosarcoma of the liver and hepatocellular carcinoma.[3] There is strong evidence from both human and animal studies that vinyl chloride causes cancer via a genotoxic mechanism.[3]

Acute inhalation exposure to vinyl chloride can cause dizziness, nausea, headache, fatigue, visual and hearing disturbances, sleep disturbances, unconsciousness, and in high concentrations, death.[4,5] 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.[4,5]

Regulations and Guidelines

Occupational exposure limits (OEL)[6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]

ppm = parts per million
stel = short term exposure limit (15 min. maximum)
em = exposure must be reduced to the minimum
* Written notice to Ministry of Labour Relations and Workplace Safety required for use and disposal
ACGIH = American Conference of Governmental Industrial Hygienists
TLV = threshold limit value

Canadian environmental guidelines and standards*

Canadian agencies/organizations

Canadian Production and Trade

There is little evidence to suggest that vinyl chloride is being produced in any large quantity in Canada. Canadian demand for vinyl chloride is currently met with imports, mainly from the US.[40]

Production and trade

Environmental Exposures Overview

Potential sources of environmental exposure to vinyl chloride include inhaling contaminated air, ingesting contaminated drinking water and foods, and using PVC consumer products.[1] Overall, exposure levels for vinyl chloride are expected to be very low in the general population.[1]

Vinyl chloride is released into the environment from vinyl chloride and PVC manufacturers.[3] Higher air concentrations of vinyl chloride have been found in communities located within close proximity to these sites.[1,4] Levels of vinyl chloride in areas not within close proximity to emission sources are generally very low.[1,3] The National Air Pollution Surveillance Network found that between 2003 and 2006, 99% of samples were below the limit of detection.[41]

Drinking water may become contaminated by industrial release of vinyl chloride or leaching of its monomers in PVC piping.[42] In the 1990’s and 2000’s, several provinces tested their drinking water for vinyl chloride; levels of vinyl chloride were generally below the detection limit, except for in Quebec and Alberta, where 0.4% and 0.1% of samples, respectively, exceeded the detection limit.[42] One study found that drinking water passing through new PVC pipes contained higher levels of vinyl chloride compared to water passing through nine-year-old pipes.[43] However, ingesting drinking water is not expected to expose the majority of the general population to vinyl chloride.[1,4]

Regulations in Canada prohibit using materials that could allow leaching of vinyl chloride in food packaging.[44] The 2007 Canadian Total Diet Study found that vinyl chloride was not detected in any of the 153 samples tested.[45] Exposure to vinyl chloride from food and beverage consumption is estimated at 0.1 µg/day.[42]

PVC consumer products may contain very small residual amounts of vinyl chloride.[3] In the 1970s, residual vinyl chloride was found in products such as vinyl music records, plastic food bottles, kitchen wrapping films, and bathroom tiles.[3] Recent improvements to manufacturing processes have substantially reduced the levels of residual vinyl chloride in PVC products.[3]

Vinyl chloride is found in smoke from cigarettes (1.3-16 ng/cigarette), cigars (14-27 ng/cigar), and marijuana cigarettes (5.4 ng/cigarette).[1,3]

Searches of Environment Canada’s National Pollutant Release Inventory (NPRI) and the US Consumer Product Information Database yielded the following results on current potential for exposure to vinyl chloride in Canada:

NPRI and US Consumer Product Information Database

t = tonne

Occupational Exposures

Inhalation is the most important route of occupational exposure to vinyl chloride, although skin absorption may also occur.[3,4]

The main occupations exposed to vinyl chloride include workers involved in producing vinyl chloride monomer and using vinyl chloride during PVC and other chemical production.[1]

In plants where vinyl chloride monomer is produced, exposures generally occur after production, when the monomer product is being transported and stored, or during equipment maintenance.[1]

Exposure may occur during PVC polymerization or synthesis of other chemicals, if vinyl chloride is released into the air.[1] 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.[3,4]

North American and Western European countries introduced new occupational exposure limits for vinyl chloride in the 1970s, after recognizing the chemical’s carcinogenic effects.[3,4] By the late 1970s, many PVC manufacturers in these countries began using “closed-loop” polymerizing systems, which substantially reduced occupational exposures to vinyl chloride.[3,4]

CAREX Canada has not prioritized vinyl chloride for exposure estimate development. This is because the likelihood of exposure in Canadian workers is very low.

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