1,1,2-Trichloroethane

1,1,2-Trichloroethane (also called vinyl trichloride) was produced industrially as an intermediate in manufacturing vinylidene chloride and polyvinylidene chloride (PVDC) — the plastic used in food wraps like Saran Wrap [1]. It also served as a solvent in adhesives, metal cleaning, and textile processing from the 1940s through the 1980s. Because it was considered less acutely toxic than carbon tetrachloride, it was used without the same precautions — resulting in widespread soil and groundwater contamination at industrial sites, dry cleaners, and military bases [2]. EPA placed 1,1,2-trichloroethane on the Superfund priority list and set a Maximum Contaminant Level of 0.005 mg/L in drinking water. It is still produced as a chemical intermediate but regulated industrial releases have declined significantly in the U.S.; legacy contamination persists at hundreds of sites [1].

Contaminated groundwater is the primary exposure route: private wells and some municipal supplies near former industrial or dry-cleaning sites may contain 1,1,2-trichloroethane [1]. Volatilization from contaminated soil into building air — a process called vapor intrusion — is a significant secondary pathway; basements and lower floors of buildings on former industrial land can have elevated air concentrations [2]. Occupational exposure continues in chemical manufacturing settings where it is produced as an intermediate [1]. Consumer products containing chlorinated solvents are a minor route. Showering with contaminated water releases the compound into bathroom air for inhalation [2].

The liver is the primary target organ: 1,1,2-trichloroethane is metabolized to reactive intermediates that cause lipid peroxidation and hepatocellular damage [1]. Chronic occupational exposure has been associated with liver enlargement and elevated liver enzymes. EPA classifies it as a probable human carcinogen (Group B2) based on hepatocellular carcinoma in rodents at chronic doses [2]. The compound also affects the central nervous system — acute high exposure causes dizziness, incoordination, and unconsciousness; chronic lower-level exposure may contribute to neurobehavioral deficits [1]. Like related chlorinated solvents, it can degrade in groundwater to vinyl chloride — a known human carcinogen — under anaerobic conditions [2].

People relying on private wells or small water systems near former industrial, military, or dry-cleaning sites face the greatest risk [1]. Residents in buildings with vapor intrusion from contaminated soil — particularly in urban industrial districts — are continuously exposed through indoor air [2]. Children are more vulnerable because their developing livers and nervous systems are more sensitive to chlorinated solvent toxicity. Workers in chemical manufacturing and occupational settings where the compound is handled need rigorous protection [1]. People with pre-existing liver conditions (hepatitis, fatty liver disease) may be especially vulnerable to additive hepatotoxic effects [2].

1. If you have a private well near industrial sites, get it tested for chlorinated solvents through a state-certified laboratory; EPA's Safe Drinking Water Hotline (1-800-426-4791) can help locate testing resources [1]. 2. Granular activated carbon (GAC) filters remove 1,1,2-trichloroethane effectively from drinking water; reverse osmosis also works [2]. 3. If you live near a Superfund site, contact your local EPA regional office to ask about vapor intrusion assessments for your neighborhood. 4. Increase ventilation in basements and lower floors if vapor intrusion is suspected — sub-slab depressurization systems can be installed to prevent indoor air contamination [1]. 5. When showering with questionable tap water, use a bathroom exhaust fan and open windows to prevent vapor accumulation [2].