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What are Polycyclic Aromatic Hydrocarbons (PAHs)?

Ecology has finalized the
Chemical Action Plan (CAP) for PAHs
PAHs are a group of more than 100 different chemicals and generally occur as complex mixtures. They are found in some natural substances like oil and coal and are formed during the incomplete burning of organic matter such as coal, oil, gas, wood, garbage, or other organic substances, such as tobacco and meat. PAHs are released during commonplace activities, such as burning wood and driving cars, and from commonplace objects, like railroad ties.

PAHs are toxic to organisms and are widespread in Washington’s environment. PAHs are also toxic to humans and are found in people. Studies have linked PAHs to cancer, reproductive problems and weakened immune systems.

Chemical Action Plan

In 2012, Ecology released a Chemical Action Plan (CAP) for PAHs that addresses all uses and releases of PAHs in the entire state. Ecology convened an advisory committee to assist in the development of the CAP. Ecology also built on the work of the Tacoma/Pierce County Clean Air Task Force.

The CAP found the largest man-made sources to the environment are from wood burning stoves, creosote treated wood, and vehicle emissions, including tire wear, improper motor oil disposal and leaks. For most individuals, the largest exposures to PAHs are from food and smoking, with a lesser contribution from air emissions.

There are current programs in place in Washington to address the major sources of concern. These programs can be enhanced to improve or speed up results, but we did not find that major new programs are needed.

The Departments of Ecology and Health have existing programs to reduce PAH releases from complex mixtures, such as wood smoke, diesel, and creosote. Many other individuals and groups are also working to reduce emissions from combustion including businesses, other state and federal agencies, local air agencies, counties, ports, cities, and not-for-profit organizations.

The recommendations focus on initial sources of PAHs, but it is also important to manage pathways through which PAHs from multiple sources reach people and the environment. Developing more effective strategies for controlling stormwater is an important tool in limiting the impact of PAHs in Washington.

Major recommendations to protect human health and the environment include:

Wood smoke Education, outreach, and voluntary incentive programs to reduce wood smoke emissions.
Local clean air agencies may prohibit the use of uncertified wood stoves in specified areas that are out of attainment with federal air standards.
Support new federal standards for wood burning devices.
Vehicles Education, outreach, and incentives to reduce fuel consumption, reduce automotive drips and leaks, and reduce vehicle idling.
Continue anti-idling education programs and write an anti-idling rule.
Continue Ecology's current strategy to reduce diesel pollution.
Support new federal actions on automotive efficiency, cleaner burning fuel, and lowering diesel emissions.
Creosote-treated wood and other products Continue creosote piling removal of derelict structures.
Map railroad tie locations near sensitive habitats.
Monitor uses and environmental fate of PAHs from other PAH-containing products, like asphalt shingles and roofing.
Human health Continue anti-smoking programs and work to enhance them in the future.
Develop outreach on food preparation methods that reduce exposure to PAHs.

Coal Tar Sealants

Coal tar and asphalt-based sealants are black liquids that are sprayed or painted on asphalt parking lots and driveways. Published studies have identified coal tar sealant as a potentially important source of PAHs. RCW 70.295, passed in 2011, prohibits the sale and application of coal tar pavement sealants in Washington State. A retailer may not sell coal tar pavement products after January 1, 2012, and no person may apply a coal tar pavement product on a driveway or parking area after July 1, 2013.