- At room temperature, vinyl chloride is a colorless, highly flammable, potentially explosive gas.
- The primary target of vinyl chloride acute exposure is the CNS. Signs and symptoms include dizziness, ataxia, inebriation, fatigue, numbness and tingling of the extremities, visual disturbances, coma, and death.
- Chronic exposure can cause permanent liver injury and liver cancer, neurologic or behavioral symptoms, and changes to the skin and bones of the hand.
Inhalation
Inhalation is the primary route of exposure, and vinyl chloride is readily absorbed from the lungs. Its odor threshold is too high to provide an adequate warning of hazardous concentrations. The odor of vinyl chloride becomes detectable at around 3,000 ppm and the OSHA PEL is 1 ppm (8-hour TWA). Therefore, workers can be overexposed to vinyl chloride without being aware of its presence. A 5-minute exposure to airborne concentrations of 8,000 ppm can cause dizziness. As airborne levels increase to 20,000 ppm, effects can include drowsiness, loss of coordination, visual and auditory abnormalities, disorientation, nausea, headache, and burning or tingling of the extremities. Exposure to higher concentrations of vinyl chloride for longer durations can cause death, presumably due to central nervous system (CNS) and respiratory depression. The gas is heavier than air and can cause asphyxiation in poorly ventilated or enclosed spaces.
Children exposed to the same levels of vinyl chloride as adults may receive a larger dose because they have greater lung surface area:body weight ratios and increased minute volumes:weight ratios. In addition, they may be exposed to higher levels than adults in the same location because of their short stature and the higher levels of vinyl chloride found nearer to the ground.
Respiratory
Vinyl chloride gas inhalation can cause mild respiratory tract irritation, wheezing, and chemical bronchitis. These effects are transient and resolve quickly following removal from exposure. Death may result from respiratory depression.
Carcinogenicity
The U.S. Department of Health and Human Services (DHHS) and the International Agency for Research on Cancer (IARC) have classified vinyl chloride as a known human carcinogen. Vinyl chloride has caused angiosarcoma of the liver in heavily exposed.
Reproductive and Developmental Effects
Vinyl chloride is included in Reproductive and Developmental Toxicants, a 1991 report published by the U.S. General Accounting Office (GAO) that lists 30 chemicals of concern because of widely acknowledged reproductive and developmental consequences. However, there is no conclusive evidence of reproductive or developmental effects in humans. A few case reports describe decreased libido or fertility in men with chronic occupational exposure, and some animal studies also support this finding. Some studies in experimental animals have reported developmental toxicity associated with high-dose exposures, but vinyl chloride is not considered a developmental toxicant.
Special consideration regarding the exposure of pregnant women is warranted, since vinyl chloride has been shown to be a genotoxin; thus, medical counseling is recommended for the acutely exposed pregnant women.
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For more information log on to http://www.atsdr.cdc.gov/MHMI/mmg20.html
In the following posts I will bring in more details from a report by Dr.Mark Chernaik
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