What are PAHs, coal tar, and sealcoat?
Polycyclic aromatic hydrocarbons (or PAHs) are a group of organic contaminants that form from the incomplete combustion of hydrocarbons, such as coal and gasoline. PAHs are an environmental concern because they are toxic to aquatic life and because several are suspected human carcinogens. Coal tar is a byproduct of the coking of coal, and can contain 50 percent or more PAHs by weight. Sealcoat is a black liquid that is sprayed or painted on asphalt pavement in an effort to protect and beautify the asphalt. Most sealcoat products are coal-tar or asphalt based. Many coal-tar sealcoat products contain as much as 30 percent coal tar by weight. Product analyses by the City of Austin indicated that coal-tar sealcoat products have median concentrations of total PAHs about 70 times higher than concentrations in asphalt-based sealcoat products. Sealcoat is used commercially and by homeowners across the Nation. It is applied to residential driveways and to parking lots associated with commercial
