Vinyl chloride toxicity

Last revised by Dr Daniel J Bell on 20 May 2022

Vinyl chloride toxicity (and polyvinyl chloride) may rarely result from occupational exposure, most notably manifesting as chronic liver disease and rare hepatic malignancies. However due to strict regulation of the industrial manufacturing and processing of vinyl chloride since the 1970s, significant exposure is now very unusual.

Vinyl chloride monomer and polyvinyl chloride exposure significant enough to result in harm is now very rare and generally historical. From its introduction into industry in the 1920s until new regulations in the 1970s, virtually all toxicity was from occupational exposure. Significant toxicity from accidental releases into the environment has not been documented 4.

The polymerization of vinyl chloride takes place in an autoclave vessel and over time deposits of polyvinyl chloride (PVC) accumulate on its walls. In the past, plant workers had to manually enter the vessel and scrape the PVC from the walls exposing them to extremely high concentrations of residual vinyl chloride gas. Pressure washers and solvents were introduced in the 1970s to avoid these exposures, and significant toxicity became much rarer 4.

The commonest severe disease association is with hepatic pathologies, including cirrhosis, chronic liver disease and malignancies with a long latency (20 years) between first exposure and malignant presentation 1.

Vinyl chloride monomer (VCM) is a manufactured gas used in the synthesis of polyvinyl chloride (PVC), a well-known and extensively-employed plastic. Most toxicity from vinyl chloride is due to occupational exposure in the manufacture and processing of vinyl chloride monomers and polyvinyl chloride 1

Vinyl chloride monomer is known to cause genetic mutations, for example of TP53 and KRAS, and chromosomal aberrations 1.  

Exposure to high concentrations of vinyl chloride gas sometimes resulted in what was known as vinyl chloride disease, which was a characterized by a wide range of signs and symptoms 4:

Complications tend to have a long latency period, e.g. approximately 20 years for hepatic angiosarcoma.

Hepatic toxicity to vinyl chloride was first recognized in 1948, but it was not until 1974 that there were reports of angiosarcoma of the liver in two individuals working in the plastic manufacture industry 3.

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