U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Dense Nonaqueous Phase Liquids (DNAPLs)

Environmental Occurrence

Halogenated Alkanes


1,1-Dichloroethane (1,1-DCA) is released to the atmosphere primarily through emissions from industrial factories where it is produced as a chemical intermediate to form other products. While in the atmosphere, 1,1-DCA can travel long distances before being washed out by rain (ATSDR 1990).

1,1-DCA has been used as a coupling agent in antiknock gasoline; as a metal degreasing agent; in paint, varnish and finish removers; for organic synthesis; and in ore flotation (Verschueren 1983).

EPA's Toxics Release Inventory shows that 6,555 pounds of 1,1-DCA was released to the environment in 2008, of which 6,282 pounds was released to the air. As some releases do not meet EPA's reporting requirements, this number must be considered a minimum estimate.

The compound also is released from landfills, where research shows that 1,1,1-trichloroethane, which is one of the chemicals most commonly found at Superfund sites, can biodegrade in the landfill's anaerobic methanogenic environment to form 1,1-DCA (ATSDR 1990).

An on-line search of EPA's CERCLIS database using 1,1-dichloroethane as a keyword returned 285 sites. A random sample of these sites indicates that 1,1-DCA generally is found in a mixture of organic chemicals.

A study performed by the Environmental Working Group (EWG) on 25,467 public water suppliers in 38 states showed that 7.0 million people in 108 communities drank water contaminated with 1,1-DCA between 1998 and 2003. In two of these communities, tap water was contaminated at levels above the human-health threshold (EWG).

1,1-DCA was found in about one percent of the aquifer samples obtained in a study by the U.S. Geological Survey (Zogorski et al. 2006). Although the compound was found in about two percent of the public well samples, 1,1-DCA was not detected in any of the private domestic well samples.


Handbook of Environmental Data on Organic Chemicals, Second Edition
Verschueren, K.
Van Nostrand Reinhold Co., New York, 1983

National Drinking Water Database
Environmental Working Group (EWG).

The Quality of Our Nation's Waters: Volatile Organic Compounds in the Nation's Ground Water and Drinking-Water Supply WellsAdobe PDF Logo
Zogorski, J., J.M. Carter, T. Ivahnenko, W.W. Lapham, M.J. Moran, B.L. Rowe, P.J. Squillace, and P.L. Toccalino.
U.S. Geological Survey Circular 1292, 112 pp, 2006

Toxicological Profile for 1,1,-Dichloroethane
Agency for Toxic Substances and Disease Registry (ATSDR), 116 pp, 1990