EPA issued a September 2011 report - Assessment of Water Quality of Runoff from Sealed Asphalt Surfaces - that found coal-tar sealants create polycyclic aromatic hydrocarbons (PAHs) runoff in amounts up to 1,000 times greater than the alternative asphalt-emulsion sealant, which is used mostly in western states. Runoff tests from recently sealed asphalt surfaces were conducted at the EPA Urban Watershed Research Facility (UWRF) in Edison, New Jersey. According to the report, coal-tar sealant has been shown to have a detrimental effect on the overall health of a variety of aquatic organisms. The study found that sealants applied to asphalt surfaces leached measurable quantities of PAHs. Results indicated that the time from the initial sealant application is a major factor in observed PAH concentration in runoff. The highest PAH concentrations measured were in initial runoff samples where sampling was performed twenty-four hours after application of sealants to the asphalt surface.
An April 14, 2011 briefing sponsored by Rep. Lloyd Doggett (D–TX) and hosted by the U.S. Geological Survey (USGS), in cooperation with WEF; and the Environmental and Energy Study Institute (EESI) focused on findings by the USGS National Water-Quality Assessment (NAWQA) Program on PAHs in urban lakes related to pavement sealant use in 40 cities. The findings, similar to those in the EPA study, showed that coal-tar-based pavement sealants are a much larger source of PAHs to urban lakes than previously identified sources, such as vehicle emissions, used motor oil, and tire particles. Also, other USGS studies show that levels of PAHs in the dust of residences adjacent to parking lots with these sealants are about 25 times higher than in the dust of residences near other surface types.