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Fact Sheet 2011–3010

Coal-Tar-Based Pavement Sealcoat, Polycyclic Aromatic Hydrocarbons (PAHs), and Environmental Health

By B.J. Mahler and P.C. Van Metre


Thumbnail of and link to FS report (3.24 MB)

Studies by the U.S. Geological Survey (USGS) have identified coal-tar-based sealcoat—the black, viscous liquid sprayed or painted on asphalt pavement such as parking lots—as a major source of polycyclic aromatic hydrocarbon (PAH) contamination in urban areas for large parts of the Nation. Several PAHs are suspected human carcinogens and are toxic to aquatic life.

First posted February 9, 2011

For additional information contact:
Director, Texas Water Science Center
U.S. Geological Survey
1505 Ferguson Lane
Austin, TX 78754-4501

World Wide Web:

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Suggested citation:

Mahler, B.J., and Van Metre, P.C., 2011, Coal-tar-based pavement sealcoat, polycyclic aromatic hydrocarbons (PAHs), and environmental health: U.S. Geological Survey Fact Sheet 2011–3010, 6 p.


Key Findings

What are Sealcoat, PAHs, and Coal Tar?

How does Sealcoat get from Driveways and Parking Lots into Streams and Lakes, Homes, and the Air?

The East-West Divide—Regional Product Use Translates to Large Differences in PAH Concentrations

“Fingerprinting” Shows that Coal-Tar Sealant is the Largest Source of PAHs to Urban Lakes

From Outside to Inside—Coal-Tar Pavement Sealant Linked to PAHs in House Dust

Our Environment and Us—What are the Concerns?



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