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Water: Basic Information about Regulated Drinking Water Contaminants

Basic Information about Benzo(a)pyrene in Drinking Water

Benzo(a)pyrene at a Glance

Maximum Contaminant Level (MCL) = 0.0002 milligrams per Liter (mg/L) or 200 nanograms per Liter (nanograms/L)

Maximum Contaminant Level Goal (MCLG) = zero

Health Effects
Some people who drink water containing benzo(a)pyrene in excess of the MCL over many years may experience reproductive difficulties and may have an increased risk of cancer.

Drinking Water Health Advisories provide more information on health effects

Chemical Abstract Service Registry Number
50-32-8

Sources of Contamination
Leaching from linings of water storage tanks and distribution lines

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

EPA regulates benzo(a)pyrene in drinking water to protect public health. Benzo(a)pyrene 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 benzo(a)pyrene?
Benzo(a)pyrene is one of a group of compounds called polycyclic aromatic hydrocarbons.

Uses for benzo(a)pyrene
They are not produced or used commercially but are very commonly found since they are formed as a result of incomplete combustion of organic materials.

If you are concerned about benzo(a)pyrene in a private well, please visit:

What are benzo(a)pyrene's health effects?
Some people who drink water containing benzo(a)pyrene well in excess of the maximum contaminant level (MCL) for many years may experience reproductive difficulties and may have an increased risk of cancer.

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

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What are EPA's drinking water regulations for benzo(a)pyrene?
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 benzo(a)pyrene is zero. EPA has set this level of protection based on the best available science to prevent potential health problems. EPA has set an enforceable regulation for benzo(a)pyrene, called a maximum contaminant level (MCL), at 0.0002 mg/L or 200 nanograms/L. MCLs are set as close to the health goals as possible, considering cost, benefits and the ability of public water systems to detect and remove contaminants using suitable treatment technologies.

The Phase V Rule, the regulation for benzo(a)pyrene, became effective in 1994. 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 benzo(a)pyrene as part of the Six Year Review and determined that the zero MCLG and 0.0002 mg/L or 200 nanograms/L MCL for benzo(a)pyrene are still protective of human health.

States may set more stringent drinking water MCLGs and MCLs for benzo(a)pyrene than EPA.

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How does benzo(a)pyrene get into my drinking water?
The major source of benzo(a)pyrene in drinking water is leaching from linings of water storage tanks and distribution lines.

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 benzo(a)pyrene is in my drinking water?
When routine monitoring indicates that benzo(a)pyrene levels are above the MCL, your water supplier must take steps to reduce the amount of benzo(a)pyrene so that it is below that level. 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 benzo(a)pyrene be removed from my drinking water?
The following treatment method(s) have proven to be effective for removing benzo(a)pyrene to below 0.0002 mg/L or 200 nanograms/L: Granular activated carbon.

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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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