Vinyl Chloride

Vinyl chloride is an organic compound widely used in a number of industries. The most common use being the production of PVC pipe and material. Due to it’s boiling point of -13°C, at room temperature it is a gas easily detectable by it’s distinct sweet odor. On combustion it produces several gases including carbon monoxide, carbon dioxide, hydrogen chloride and small amounts of phosgene. (Health 2001) OSHA regulations limit the permissible exposure limit (PEL) to 1ppm as an 8 hour time weighted average and a 5ppm ceiling for any 15 minute period.
Research into the health effects of vinyl chloride has been ongoing for many years. Due to it’s known toxicity and carcinogenic effects most of the studies were done on groups who had previous exposure, primarily workers in the chemical and PVC industries. Other studies were conducted on animal subjects which allowed more control over the exposure method, time and dose.
In determining the carcinogenicity of vinyl chloride two methods were primarily used, ingestion studies and inhalation studies. These studies used various doses and time spans to determine carcinogenicity. In these studies vinyl chloride was shown to cause tumors in a dose related manner at several sites including liver, lung and mammary glands. The response appears as a function of a number factors including site, chemical concentration, test subject and route of exposure. (Assessment 2000) One study exposed rats of various ages to identical levels of vinyl chloride. Rats and mice were exposed at 8 weeks, 6 months or 1 year of age. The subjects exposed at 8 weeks showed decreased survival rates while the 2 other groups showed no decrease in survival rates. (Assessment 2000)
The studies of human subjects have not been as controllable due to the known toxicity of vinyl chloride. Because of factors such as lifestyle and genetics there may be other factors contributing to the carcinogenicity of vinyl chloride. Alcohol use and aflatoxins have both been shown to cause liver damage but cannot be controlled in human study groups to the degree animal studies allow.


References

Agency, Environmental Protection. Vinyl Chloride TEACH Chemical Summary. 10 1, 2007. http://www.epa.gov/teach/chem_summ/VC_summary.pdf (accessed 03 19, 09).
Assessment, Office of Environmental Health Hazard. Public Health Goals for Chemicals in Drinking Water. 10 01, 2000. http://www.oehha.ca.gov/water/phg/pdf/vinylch.pdf (accessed 03 19, 2009).
Diseases, Agency for Toxic Substances &. Toxicological Profile. July 1, 2006. http://www.atsdr.cdc.gov/toxprofiles/tp20.html#bookmark11 (accessed 03 19, 2009).
Health, National Institute of. Vinyl Chloride. 10 07, 2001. http://www.mindfully.org/Plastic/Vinyl-Chloride-9thROC.htm (accessed 03 19, 2009).
Services, New Jersey Department of Health and Senior. Hazardous Substance Fact Sheet. 12 01, 2001. http://nj.gov/health/eoh/rtkweb/documents/fs/2001.pdf (accessed 03 1, 2009).