1,1,2,2-Tetrachloroethane


Disclaimer

Introduction

1,1,2,2-Tetrachloroethane is a man-made, colorless, dense liquid that does not burn easily, and has a penetrating, sweet, chloroform-like odor. It is now produced by only one company in the United States. It had been used in large amounts to produce other chemicals and as an industrial solvent. 1,1,2,2-Tetrachloroethane was also used to separate other substances, to clean and degrease metals, and in paints and pesticides. Its present use appears to be limited, and information about its use is unavailable. Information about its production volume is protected by the manufacturer. Therefore, it is not possible to say how much of this chemical is used, where it is used, or in what products it is found. Patterns of its use can best be determined from surveys of industrial wastewater.

Structural diagram: National Institutes of Health


Fate & Transport

Most 1,1,2,2-tetrachloroethane released into the environment eventually moves in the outside air or groundwater. Breakdown of this chemical in both the air and groundwater is slow. Half of the chemical is expected to disappear from groundwater in 1-3 months and from air in about 2 months.

Exposure Pathways

Low levels of 1,1,2,2-tetrachloroethane can be present in both indoor and outdoor air. Test studies of city areas show that it is present in only a small number of air samples. Its average concentration in certain city air could be as high as 57 parts per billion (ppb) (57 parts in 1,000,000,000 parts). The most typical air concentration is about 5 parts per trillion (ppt) (5 parts in 1,000,000,000,000 parts) or less. The average concentrations of 1,1,2,2-tetrachloroethane in the indoor air of several homes was 1.8 ppb. Because the air outside these homes did not contain measurable amounts of 1,1,2,2-tetrachloroethane, the source of the chemical appears to be products used within these homes.

1,1,2,2-Tetrachloroethane can be present in water, and the most representative survey of surface water and groundwater, conducted in the highly industrialized state of New Jersey in 1977-1979, found 6% of groundwater and 11% of surface water contaminated with 1,1,2,2-tetrachloroethane. The highest levels found were 2.7 parts of 1,1,2,2-tetrachloroethane in one billion parts of groundwater (ppb) and 3 ppb in surface water. The New Jersey survey included water supplies used for drinking and water not used for drinking. Although individuals may be exposed to 1,1,2,2-tetrachloroethane from contaminated drinking water, such occurrences are extremely rare. A nationwide survey of drinking water taken from underground sources did not find any supplies containing this pollutant. In a few instances, 1,1,2,2-tetrachloroethane was found in private well water that may be used for drinking. 1,1,2,2-Tetrachloroethane has not been reported in food or soil. It is not expected to build up in the food chain.

In addition to exposures in air and drinking water, occupational exposures to 1,1,2,2-tetrachloroethane may result from spills and other accidents or normal operations in workplaces. The compound is used as a solvent for many operations, as a cleaning agent for metals, as a paint remover, as a part of varnishes and lacquers, or for removing oils and fats. Exposure would most likely be by breathing in vapors of the chemical or from skin contact. When a chemical such as 1,1,2,2-tetrachloroethane is used in making other chemicals, it is generally in automatic systems which are not open to the air. Therefore, worker exposure to high levels of 1,1,2,2-tetrachloroethane do not usually occur. A national survey conducted in 1981-1983 estimated that 4143 workers are exposed to 1,1,2,2-tetrachloroethane. However, the use of this chemical has reportedly decreased since 1983, so the number of exposed workers may now be much lower.

1,1,2,2-Tetrachloroethane was found at at least 59 of the 1177 hazardous waste sites on the National Priorities List (NPL) and landfill gases released from these sites may contain 1,1,2,2-tetrachloroethane. However, 1,1,2,2-tetrachloroethane has not been reported in landfill gases. Studies show that 1,1,2,2-tetrachloroethane is slowly changed to other chemicals, including vinyl chloride, in landfills and groundwater. Vinyl chloride is likely to be more harmful to health than 1,1,2,2-tetrachloroethane.

Metabolism

1,1,2,2-Tetrachloroethane can enter the body when a person breathes air containing the chemical or when a person's skin comes into contact with the chemical. If you accidentally drank some or drank water containing it, 1,1,2,2-tetrachloroethane would be absorbed into your body. Most of it leaves the body fairly quickly (within a few days) through the breath or through the urine.

Health Effects

1,1,2,2-Tetrachloroethane is not life-threatening unless you intentionally or accidentally drink more than a few spoonfuls at one time or spill a large amount (a bucketful) on you so that you breathe it in and get it on your skin. Breathing highly concentrated fumes of 1,1,2,2-tetrachloroethane (enough so that you notice its sickeningly sweet smell) can cause fatigue, vomiting, dizziness, and possibly unconsciousness. Most people will recover once they are in fresh air. Breathing or drinking smaller amounts may cause liver damage, stomachaches, or dizziness, but you must be exposed to high enough amounts so that you can smell it, or you need to dip your hands into the chemical for a long period of time. The human health effects from long-term exposure to rather small amounts of 1,1,2,2-tetrachloroethane are not known. Not enough information is available to determine whether exposure to 1,1,2,2-tetrachloroethane will cause reproduction problems, defects, or cancer in humans.

Some people who breathed the fumes and also put their hands into this chemical while using it in a factory, became sick with stomach pains, shakiness, and headaches. The smell of 1,1,2,2-tetrachloroethane is noticeable when it is in air at levels more than 1.5 parts of 1,1,2,2-tetrachloroethane in one million parts of air (ppm). We do not know whether 1,1,2,2-tetrachloroethane causes cancer in humans.

Information excerpted from:

Toxicological Profile for 1,1,2,2-Tetrachloroethane December 1989

Agency for Toxic Substances and Disease Registry
U.S. Dept. of Health and Human Services