Consumer Factsheet on: DICHLOROMETHANE
List of Contaminants
As part of the Drinking Water and Health pages, this fact sheet is part of a larger publication:
National Primary Drinking Water Regulations
This is a factsheet about a chemical that may be found in some public or private drinking water supplies.
It may cause health problems if found in amounts greater than the health standard set by the United
States Environmental Protection Agency (EPA).
What is DCM and how is it used?
Dichloromethane (DCM) is a colorless organic liquid with a sweet, chloroform-like odor. The greatest use
of DCM is as a paint remover. Other uses include: solvent and cleaning agent in a variety of industries, a
fumigant for strawberries and grains; and to extract substances from foodstuffs.
The list of synonyms given below may help you find out whether you are using this chemical at home or
work.
Trade Names and Synonyms:
DCM
Methylene chloride
Why is DCM being Regulated?
In 1974, Congress passed the Safe Drinking Water Act. This law requires EPA to determine safe levels of
chemicals in drinking water which do or may cause health problems. These non-enforceable levels,
based solely on possible health risks and exposure, are called Maximum Contaminant Level Goals.
The MCLG for dichloromethane has been set at zero because EPA believes this level of protection would
not cause any of the potential health problems described below.
Based on this MCLG, EPA has set an enforceable standard called a Maximum Contaminant Level (MCL).
MCLs are set as close to the MCLGs as possible, considering the ability of public water systems to detect
and remove contaminants using suitable treatment technologies.
The MCL has been set at 5 parts per billion (ppb) because EPA believes, given present technology and
resources, this is the lowest level to which water systems can reasonably be required to remove this
contaminant should it occur in drinking water.
These drinking water standards and the regulations for ensuring these standards are met, are called
National Primary Drinking Water Regulations. All public water supplies must abide by these regulations.
What are the Health Effects?
Short-term: EPA has found dichloromethane to potentially cause the following health effects when people
are exposed to it at levels above the MCL for relatively short periods of time: Damage to the nervous
system and to blood.

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Long-term: Dichloromethane has the potential to cause the following effects from a lifetime exposure at
levels above the MCL: liver damage; cancer.
How much DCM is produced and released to the environment?
Production of DCM has been decreasing: from a high of 561 million lbs. in 1986, to roughly 410 million
lbs. in 1993. It is released in wastewater primarily from the following industries: Paint and ink, aluminum
forming, coal mining, photographic equipment and supplies, pharmaceutical, organic chemical/plastics,
metal foundries and laundries. DCM is also formed during the chlorination of water.
From 1987 to 1993, according to EPA's Toxic Chemical Release Inventory, DCM releases to land and
water totalled over 2.1 million lbs. These releases were primarily from medicinals and botanicals
industries. The largest releases occurred in Connecticut and New York.
What happens to DCM when it is released to the environment?
Most DCM is released to air where it is degraded by sunlight within a few months. Releases to water
evaporate very quickly. It will evaporate from soil but can also leach through soil to ground water. DCM is
not likely to accumulate in aquatic life.
How will DCM be Detected in and Removed from My Drinking Water?
The regulation for dichloromethane became effective in 1994. Between 1993 and 1995, EPA required
your water supplier to collect water samples every 3 months for one year and analyze them to find out if
dichloromethane is present above 0.5 ppb. If it is present above this level, the system must continue to
monitor this contaminant.
If contaminant levels are found to be consistently above the MCL, your water supplier must take steps to
reduce the amount of dichloromethane so that it is consistently below that level. The following treatment
methods have been approved by EPA for removing dichloromethane: Granular activated charcoal in
combination with Packed Tower Aeration.
How will I know if DCM is in my drinking water?
If the levels of dichloromethane exceed the MCL, 5 ppb, the system must notify the public via
newspapers, radio, TV and other means. Additional actions, such as providing alternative drinking water
supplies, may be required to prevent serious risks to public health.
Drinking Water Standards:
Mclg: zero
Mcl: 5 ppb
DCM Releases to Water and Land, 1987 to 1993 (in pounds):
TOTALS (in pounds)
Top Ten States*
Water
1,544,694
Land
556,830
CT
NY
GA
NJ
Wl
940,158
58,400
166,700
138,302
0
0
155,755
0
2,721
139,920

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sc
20,860
39,575
0
52,810
32,900
33,489
27,295
823
Ml
KS
MO
TX
Major Industries*
Medicinals, botanicals
Photographic supplies
Misc Indust. organics
Custom plastics, resins
Pharmaceuticals
Potato/corn chips&snacks
Air conditioning/heating
Steel pipe, tubing
0
15,910
1,106,858
58,400
141,942
0
37,575
2,000
0
0
0
155,755
53,741
139,920
0
32,900
33,489
27,295
* Water/Land totals only include facilities with releases greater than a certain amount - usually 1000 to
10,000 lbs.
Learn more about your drinking water!
EPA strongly encourages people to learn more about their drinking water, and to support local efforts to
protect and upgrade the supply of safe drinking water. Your water bill or telephone books government
listings are a good starting point.
Your local water supplier can give you a list of the chemicals they test for in your water, as well as how
your water is treated.
Your state Department of Health/Environment is also a valuable source of information.
For help in locating these agencies or for information on drinking water in general, call: EPAs Safe
Drinking Water Hotline: (800) 426-4791.
For additional information on the uses and releases of chemicals in your state, contact the: Community
Right-to-Know Hotline: (800) 424-9346.

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