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Water: Basic Information about Regulated Drinking Water Contaminants

Basic Information about Epichlorohydrin in Drinking Water

Epichlorohydrin at a Glance

Treatment Technique Requirement: 
EPA has regulated epichlorohydrin using a treatment technique requirement because of the absence of a standardizied analytical method for its measurement in drinking water.

The Phase II rule, which includes the regulation for epichlorohydrin, limits the allowable residual epichlorohydrin (an impurity) in the polymeric coagulant aids, to 0.01 percent by weight and the dosage of polymeric coagulant aid which can be added to raw water to remove particulates, to 20 parts per million (ppm). 

Each water system is required to certify, in writing to the primacy authority, that it meets these requirements when using epichlorohydrin- based coagulant aids.  A water system may use third-party or manufacturer certification in lieu of testing for the residual monomer level.

Maximum Contaminant Level Goal (MCLG) = zero

Health Effects
Some people who drink water containing high levels of epichlorohydrin over a long period of time could experience stomach problems and may have an increased risk of getting cancer.

Drinking Water Health Advisories provide more information on health effects

Chemical Abstract Service Registry Number
106-89-8

Sources of Contamination
Discharge from industrial chemical factories; an impurity of some water treatment chemicals

List of all Regulated Contaminants (PDF) (6pp, 396 K, about PDF)

EPA regulates epichlorohydrin in drinking water to protect public health. Epichlorohydrin may cause health problems if present in public or private water supplies in amounts greater than the drinking water standard set by EPA.

What is epichlorohydrin?
Epichlorohydrin is a colorless organic gas with a sweet odor.

Uses for epichlorohydrin.
Epichlorhydrin is used for making glycerine and as a monomer/building block for making plastics and other polymers, some of which are used as coagulant aids in water treatment. It is also used in the paper and drug industries as an insect fumigant.

If you are concerned about epichlorhydrin in a private well, please visit:

What are epichlorohydrin’s health effects?
Some people who drink water containinghigh levels ofepichlorohydrin over a long period of time could experience stomach problems and may have an increased risk of getting cancer.

This health effects language is not intended to catalog all possible health effects for epichlorohydrin. Rather, it is intended to inform consumers of some of the possible health effects associated with epichlorohydrin in drinking water when the rule was finalized.

What are EPA’s drinking water regulations for epichlorohydrin?
In 1974, Congress passed the Safe Drinking Water Act. This law requires EPA to determine the level of contaminants in drinking water at which no adverse health effects are likely to occur. These non-enforceable health goals, based solely on possible health risks and exposure over a lifetime with an adequate margin of safety, are called maximum contaminant level goals (MCLG). Contaminants are any physical, chemical, biological or radiological substances or matter in water.

The MCLG for epichlorohydrin is zero. EPA has set this level of protection based on the best available science to prevent potential health problems.

For most contaminants, EPA sets an enforceable regulation called a maximum contaminant level (MCL) based on the MCLG. MCLs are set as close to the MCLGs as possible, considering cost, benefits and the ability of public water systems to detect and remove contaminants using suitable treatment technologies. When there is no reliable method that is economically and technically feasible to measure a contaminant at particularly low concentrations, a treatment technique is set rather than an MCL. A treatment technique is an enforceable procedure or level of technological performance which water systems must follow to ensure control of a contaminant.

EPA has regulated epichlorohydrin using a treatment technique requirement in lieu of an MCL because of the absence of standardized analytical method for its measurement in water.

The Phase II rule, which includes the regulation for epichlorohydrin, limits the amount of epichlorohydrin in the polymeric coagulant aids to 0.01 percent by weight and the dosage of polymeric coagulant aid which can be added to drinking water to remove particulates, to 20 parts per million (ppm).  Under this regulation, each water system is required to certify annually, in writing, to the Primacy authority that the coagulant aid's epichlorohydrin content and application dose do not exceed the levels specified in the rule.  A water system may use third-party or manufacturer’s certification in lieu of testing for epichlorohydrin level in coagulant aids.   

The Phase II rule became effective in 1992.  The Safe Drinking Water Act requires EPA to periodically review the national primary drinking water regulation for each contaminant and revise the regulation, if appropriate. EPA reviewed epichlorohydrin during the first Six Year Review and determined that the zero mg/L and the treatment technique requirement for epichlorohydrin were are still protective of human health.

States may set a more stringent regulatory requirement for epichlorohydrin in drinking water than EPA.

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How does epichlorohydrin get into my drinking water?
During manufacturing of the epichlorohydrin-based polymeric coagulant aids, a small amount of epichlorohydrin may remain in the coagulant aids as an impurity. When these coagulant aids are used in water treatment, there is a potential for residual epichlorohydrin to be introduced in water. Finished water may also contain epichlorohydrin because of raw water contamination from other uses of epichlorohydrin and because of leaching from epichlorohydrin based components and materials used in drinking water treatment, storage and distribution.

A federal law called the Emergency Planning and Community Right to Know Act (EPCRA) requires facilities in certain industries, which manufacture, process, or use significant amounts of toxic chemicals, to report annually on their releases of these chemicals. For more 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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How will I know if epichlorohydrin is in my drinking water?
Public water systems are required to meet the content and dosage requirements for epichlorohydrin-based polymeric coagulant aids specified in the treatment technique requirement for epichlorhydrin, and to take steps to correct the situation if they exceed these levels. Water suppliers must notify their customers as soon as practical, but no later than 30 days after the system learns of the violation. Additional actions, such as providing alternative drinking water supplies, may be required to prevent serious risks to public health.

If your water comes from a household well, check with your health department or local water systems that use ground water for information on contaminants of concern in your area. 

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How will epichlorohydrin be removed from my drinking water?
There are currently no acceptable means of detecting or removing epichlorohydrin  from drinking water.  EPA requires that its introduction in drinking water be controlled by ensuring that the coagulant aids used for water treatment and their dosage do not exceed the levels specified in the regulation. 

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How do I learn more about my drinking water?
EPA strongly encourages people to learn more about their drinking water, and to support local efforts to protect the supply of safe drinking water and upgrade the community water system. Your water bill or telephone book’s government listings are a good starting point for local information.

Contact your water utility. EPA requires all community water systems to prepare and deliver an annual consumer confidence report (CCR) (sometimes called a water quality report) for their customers by July 1 of each year. If your water provider is not a community water system, or if you have a private water supply, request a copy from a nearby community water system.

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