USGS Release: Contaminated House Dust Linked to Parking Lots with Coal Tar Sealant (1/12/2010 1:38:37 PM)

Hmm! Some of the black tar gunk that's used for sealing cracks in pavement turns out to be made from coal dust byproduct too. It also potentially contains carcinogenic particles:

"Coal-tar-based sealcoat—the black, shiny substance sprayed or painted on many parking lots, driveways, and playgrounds—has been linked to elevated concentrations of the contaminants polycyclic aromatic hydrocarbons (PAHs) in house dust."
...
"PAHs are an environmental health issue because several are probable human carcinogens and they are toxic to fish and other aquatic life."
...
"Two kinds of sealcoat products are widely used: coal-tar-emulsion based products and asphalt-emulsion based products. National use numbers are not available; however, previous research suggests that asphalt-based sealcoat is more commonly used on the West Coast, and coal-tar based sealcoat is more commonly used in the Midwest, the South, and on the East Coast."

--US Geological Survey
Here are my questions: