This is a fact sheet 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 1,2-Dichloroethylene and how is it used?
1,2-Dichloroethylene (1,2-DCE) is an odorless organic liquid that has two slightly different forms, a "cis" form and a "trans" form. Both the cis and trans forms - usually as a mixture - are used as a solvent for waxes and resins; in the extraction of rubber; as a refrigerant; in the manufacture of pharmaceuticals and artificial pearls; in the extraction of oils and fats from fish and meat; and in making other organics.
The list of trade names given below may help you find out whether you are using this chemical at home or work.
Trade Names and Synonyms:
Why is 1,2-Dichloroethylene 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
The MCLGs for 1,2-DCE have been set at 0.07 parts per million (ppm)
for the cis form, and 0.1 ppm for the trans form. EPA believes this
level of protection would not cause any of the potential health problems
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 MCLs have also been set at 0.07 ppm for the cis form, and 0.1
ppm for the trans form. 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
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 cis- and trans-1,2-DCE to potentially cause the
following health effects when people are exposed to it at levels above
the MCL for relatively short periods of time: central nervous system
Long-term: Both cis- and trans-1,2-DCE have the potential to cause
liver, circulatory and nervous system damage from long-term exposure at
levels above the MCL. The trans form is approximately twice as potent as
the cis form in its ability to depress the central nervous system.
How much 1,2-Dichloroethylene is produced and released to the
Releases to the environment are expected to be limited to manufacturing
plants in the Gulf Region of the United States. Since cis-and
trans-1,2-DCE are not listed chemicals in the Toxics Release Inventory,
data on releases during manufacture and handling are not available.
Trans-1,2-dichloroethylene may be released to the environment in
air emissions and wastewater during its production and use as a solvent
and extractant, in organic synthesis, and in the manufacture of
perfumes, lacquers, and thermoplastics.
What happens to 1,2-Dichloroethylene when it is released to the
If 1,2-dichloroethylenes are released on soil, it should evaporate and
leach into the groundwater where it will break down very slowly. If
released to water, they will mainly evaporate. Neither of the two forms
of this contaminant are likely to accumulate in aquatic life.
How will 1,2-Dichloroethylene be detected in and removed from my
The regulation for cis- and trans-1,2-DCE became effective in 1992.
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 cis-
and trans-1,2-DCE 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 cis- and
trans-1,2-DCE so that it is consistently below that level. The following
treatment methods have been approved by EPA for removing cis- and
trans-1,2-DCE: Granular activated charcoal in combination with Packed
How will I know if 1,2-Dichloroethylene is in my drinking water?
If the levels of cis- and trans-1,2-DCE exceed their MCLs, 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.
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).
Drinking Water Standards:
|Mclg: cis- 0.07 ppm; trans- 0.1 ppm
(parts per million)
Mcl: cis- 0.07 ppm; trans- 0.1 ppm
* Water/Land totals only include facilities with releases greater
than a certain amount - usually 1000 to 10,000 lbs.
Note: This fact sheet is part of a larger publication
adapted from U.S. EPA publication: EPA National Primary Drinking Water