Researchers have found high levels of a toxic chemical in the coal tar that might coat your driveway, the Chicago Tribune reports.
New studies are questioning the safety of coal tar-based sealants that are used to give asphalt a fresh look and a longer life.
They are used frequently: according to Tribune, in Lake in the Hills, about 50 miles northwest of Chicago, an estimated 89 percent of driveways are coated with coal tar. Research cited by the Tribune shows that the dust that collects as the coating crumbles is tracked into homes -- carrying very high levels of benzo(a)pyrene.
Benzo(a)pyrene is one of the chemicals in coal tar linked to cancer and other serious health problems.
Sealant manufacturers have started their own research in response to the new government and academic studies.