Blinded by Science

A decision in 2005 banning coal tar pavement sealer in Austin, TX, has snowballed in the past year causing other cities to consider regulation and the coal tar sealcoating industry to challenge the two studies that resulted in the ban to both support its product and fight the ban itself.

Industry support for coal tar is centered at the Pavement Coatings Technology Center (PCTC), a research organization in the coal tar sealcoating industry made up of more than 25 sealer producers, crude tar refiners, and others allied to the sealcoating industry. The PCTC is joined in its efforts by the American Coke & Coal Chemicals Institute (ACCCI), which represents producers of refined coal tar, the base material in coal tar sealer emulsions, to address what they believe to be grossly over-generalized conclusions relying on flawed scientific assumptions derived from minimal questionable data used to justify the Austin decision.

The Austin City ordinance, which banned use of coal tar based sealers within city limits, was rapidly passed in November 2005, and took effect January 1, 2006. By mid-2006 a group of several sealer industry companies initiated a lawsuit against the City of Austin seeking to have the State of Texas overturn the Austin ban ordinance. As of late November, this group also filed a formal complaint with U.S. Geological Survey (USGS), challenging the objectivity and data quality of a study performed by USGS researchers in Austin, which was used to justify the Austin City Council's ban.

But since Austin's decision at least one other city, Madison, WI, has taken steps to investigate its own ban of coal tar sealer. In addition, the New York Academy of Sciences (NYAS), under direction of the New York Harbor Consortium, has been conducting a series of studies to assess the impacts of various pollutants entering harbor waters carried from the Hudson and Raritan river watersheds, a 16,300-square-mile area that drains into the New York/New Jersey Harbor. Among the substances the NYAS study is examining are PAHs, the same substances that were of concern in Austin.

Plus, using the Austin studies as their basis, Senators Jim Jeffords (who has since retired) and John Warner have asked the EPA to revisit a 1992 ruling , which exempted recycling of coke oven wastes from regulation as an environmental hazard under RCRA [Resource Conservation Recovery Act]. The senators' letter cited the USGS study as having disproved assertions made by EPA more than a decade ago that coal tar-based products do not pose a risk to human health and environment. Industry members point out that the coke byproduct residue exemption to which the senators' letter refers is not relevant to the more general concerns with PAHs in the environment as expressed in the letter. EPA's exemption had nothing to do with the presence of PAHs in coal tar (or refined tars used in sealants) but was based on a comparison of constituents in products with and without recycling. Industry members say revocation of the exemption allowing blending of coke byproduct residues with coal tar would have no effect on the PAH concentrations in coal tar (or coal-tar based sealants produced from refined tar).

History of the Austin ban
PAHs (polycyclic aromatic hydrocarbons) are a group of more than 100 chemicals commonly found in the environment. Research has found that increased urbanization results in increased PAH levels, and major sources of PAH compounds to the environment are byproducts of combustion of fossil fuels in vehicle use, industrial processes, electric power generation, as well as residues of petroleum products such as gasoline, motor oil, tire wear and from other consumer products.

PAHs also result from wood burning, charcoal grilling, municipal waste discharge, and many other industries. In addition PAHs are commonly found in nature as a result of forest and prairie fires, volcanic activity, and biosynthesis by microbes and plants. Given these sources of PAHs, it's not surprising that urban areas are showing increased accumulations of PAHs in the environment.