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

Methylene Chloride

Methylene chloride (MC, CAS# 75-09-2, also known as dichloromethane) has been used as a solvent in paint strippers and removers; a propellant in aerosols; a process solvent in the manufacture of drugs, pharmaceuticals, and film coatings; a metal cleaning and finishing solvent; an agent in urethane foam blowing; and in electronics manufacturing. Aerosol products in which MC might be found include paints, automotive products, and insect sprays. The use of MC in consumer aerosol products has declined owing to labeling regulations and concerns over health and environmental issues. MC was once used in hair sprays, but this use was banned in 1989 (ATSDR 2000).

MC has also been used as an extraction solvent for spice oleoresins and hops, and for the removal of caffeine from coffee. These uses are approved by the Food and Drug Administration. MC was approved for use as a post-harvest fumigant for grains and strawberries and as a degreening agent for citrus fruit (ATSDR 2000), but the record for dichloromethane in the National Library of Medicine's Hazardous Substances Data Bank states that the active ingredient is no longer contained in any registered pesticide products.

EPA's Toxics Release Inventory reports that 4,835,669 pounds of MC (as dichloromethane) were released or disposed of in 2008. The law does not require all facilities to report, so this number must be considered a minimum estimate. Most of the releases were point source or fugitive emissions to the air (4,254,626 pounds); however, a reported 39,065 pounds total for the top 100 facilities were disposed of via Class I deep well injection.

MC was identified in at least 882 of the 1,569 hazardous waste sites that had been proposed for inclusion on EPA's National Priorities List as of 1999 (ATSDR 2000). An on-line search of EPA's CERCLIS database returned (with some overlap) 290 active sites for methylene chloride and 224 for dichloromethane.

Zogorski et al. (2006) in a nationwide survey of public and private water wells noted the presence of MC in public supply wells, sometimes at concentrations above the MCL. He also found that MC is detected in just under four percent of samples taken from aquifers, which ranks it as the fourteenth most frequently found VOC in groundwater.


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 Methylene Chloride
Agency for Toxic Substances and Disease Registry (ATSDR), U.S. Department Of Health And Human Services, 313 pp, 2000

Dichloromethane, CASRN: 75-09-2
Hazardous Substances Data Bank (HSDB)
TOXNET, National Library of Medicine Web site.