To breathe or not to breathe? That is not the question. How not to breathe known carcinogens? That is the question. If one is breathing, being near a driveway freshly sealed with coal tar involves a risk.
An article in the June 16 USA Today, “Could your driveway be making you sick?” concluded that it could. Coal-tar sealants contain up to 35 percent coal tar pitch, considered a human carcinogen by the National Toxicology Program. As the product wears off, it breaks down into particles that are then washed off into streams, blown by the wind to affect others or end up inside homes on the soles of shoes. As some of the toxic compounds evaporate into the air, sealed areas give off a strong odor.
The coal-tar sealant emits polycyclic aromatic hydrocarbons (PAHs). In a 2013 Mahler and Baylor University study, scientist E. Spencer Williams calculated that lifetime exposure to PAHs, via house dust, was 38 times higher for people living near coal-tar-sealed pavement than for those who were not. A 6-year-old already has about half of this dose and an 18-year-old, 80 percent.
Cities, states and businesses have moved to ban coal tar pavement sealants “linked to higher cancer risk and contaminated soil.” Austin, Texas passed the first ban in 2005. In May of this year, Minnesota became the second state, after Washington, to ban coal-tar pavement sealants. In April, the New York Assembly had passed a similar bill and legislation was reintroduced in the U.S. Congress. However, the sealants industry has prevented a number of bans, and continues to insist that the alternative to coal tar, the asphalt-based sealant, is inferior.
Many major retailers have already stopped selling coal-tar sealants. So, may we assume that companies paving driveways, parking lots and playgrounds have already switched over to asphalt-based products? No, not yet. Mailers, newspaper advertising and phone calls indicate that those in this area are using coal-tar sealants. While walking in my neighborhood, I asked company employees working on four driveways, “Are you using coal-tar sealant?” Two responded, and two checked with a co-worker first: All said “Yes.”
To avoid coal tar, Austin official Tom Ennis says to hire a contractor who provides an MSDA (material data safety sheet) for the product, then see if it contains the CAS number for coal tar: 65996-93-2. Do-it-yourselfers should buy only products with a “coal tar free” logo.
Byrna Weir is a Brighton resident.