Detrimental Effects of Coal Tar-Based Sealants

Pavement sealants — the black, shiny substance sprayed or painted over asphalt — are manufactured from a variety of materials, many of which cause little harm to the environment. The exception is sealants made from coal tar, which can introduce dangerous chemicals into the water supply.

Coal-based sealant is a source of polycyclic aromatic hydrocarbons (PAHs) that are toxic to aquatic life and can potentially affect human development. Coal tar-based sealants are banned in several states and many counties, but efforts to ban them in Pennsylvania have so far failed.

Over time, the sealant begins to degrade, and enters the water supply through storm water runoff. The constant abrasion from tires, snow plows, and general wear-and-tear turns the material into a fine dust, rich in PAHs, which spreads through the air and is deposited into streams and ponds every time it rains.

There are many alternative products available that are just as effective. In fact, most chain retailers, like Home Depot and Ace Hardware, have banned the sale of coal tar-based sealants.

Attached below is an article from the Virginia Coastal Policy Center that goes into greater depth on the problems with coal tar-based sealants, to help homeowners make environmentally-sensitive decisions about driveway and pavement care.