Introduction To Coal Tar Sealers and PAHs

This site was created to provide information about Refined Tar-Based Pavement Sealers. Since 2003 to the present, The City of Austin, TX (COA) and The United States Geological Survey (USGS) have been highly visible with the findings of their suspect studies, and spreading false information about Refined Tar-Based Pavement Sealers.

The City of Austin and USGS produced various studies and reports which claim that Refined Tar-Based Pavement Sealants are responsible for the majority of Polycyclic Aromatic Hydrocarbons (PAHs) pollution in pavement runoff.

This website is dedicated to show that both the City of Austin’s (COA) studies and the USGS studies have overstated the link between Refined Tar-Based Pavement Sealers and environmental PAHs. Furthermore COA and USGS presented data in a way to support preconceived beliefs of the role of Refined Tar-Based Pavement Sealants and environmental PAHs. In some studies, weak links and data gaps are downplayed or ignored. In other words, there are major fundamental flaws in these studies and therefore do not prove that Refined Tar-Based Pavement Sealers are a major source of PAHs in a watershed.

Based on the studies provided from USGS and the City, the City of Austin has banned the sale or use of Refined Tar-Based Pavement Sealers effective January 1, 2006. In a recent presentation by an official from City of Austin Watershed Protection Department stated that Austin’s coal tar sealants ban was a “precautionary” measure.

Copy of City of Austin Press Release announcing ban of Coal Tar Pavement Sealer



Dane County Wisconsin banned the sale or use of refined tar-based pavement sealers effective July 1, 2007. Dane County did no prior water or sediment testing to determine if there was even a problem or if tar sealers were the source of PAHs. Industry, local manufacturers or local applicators were allowed very little input into this process. Dane County does utilize a precautionary principle policy in environmental policy

Effective July 1, 2009, The District of Columbia banned the sale and use of refined tar-based pavement sealant. This decision was made without any input from industry, local manufacturers or local applicators. Prior to the ban, the District of Columbia commissioned a study to look at PAH sediment contamination in the Anacostia River (see link below). In this study, refined tar-based pavement sealer was not identified as a source of PAHs into the Anacostia. The District of Columbia decided to ignore the study and ban sealer anyway without any proof that the product was the source of the problem. Furthermore, the District has yet to produce any evidence that the basis behind the ban was based upon any environmental forensics investigation that identified refined tar-based pavement sealer was the primary source of PAHs in their waterway.
After the coal tar ban was adopted, the former DDOE Director announced “It’s rare that we have the chance to knock out this kind of pollution in one fell swoop.” He continued “Our nation has made substantial progress but now that we’ve discovered what’s in coal tar and what it does, we have a rare opportunity to protect our waterways relatively easily.”
Clearly it would appear that Washington DC enacted the ban on refined tar based pavement sealer on a precautionary basis.


Characterization of polycyclic aromatic hydrocarbons in urban stormwater runoff flowing into the tidal Anacostia River, Washington, DC, USA. Hwang and Foster-2006.



Precautionary Principle


The precautionary principal has been mentioned in several instances with regards to bans of refined coal tar based pavement sealers. The precautionary principle has several variations to this concept. The statement commonly found in the United State is the Wingspread Consensus Statement on the Precautionary Principle. It states: “The release and use of toxic substances, the exploitation of resources, and physical alterations of the environment have had substantial unintended consequences affecting human health and the environment. Some of these concerns are high rates of learning deficiencies, asthma, cancer, birth defects and species extinctions; along with global climate change, stratospheric ozone depletion and worldwide contamination with toxic substances and nuclear materials.
We believe existing environmental regulations and other decisions, particularly those based on risk assessment, have failed to protect adequately human health and the environment - the larger system of which humans are but a part.
We believe there is compelling evidence that damage to humans and the worldwide environment is of such magnitude and seriousness that new principles for conducting human activities are necessary.
While we realize that human activities may involve hazards, people must proceed more carefully than has been the case in recent history. Corporations, government entities, organizations, communities, scientists and other individuals must adopt a precautionary approach to all human endeavors.
Therefore, it is necessary to implement the Precautionary Principle: When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically.
In this context the proponent of an activity, rather than the public, should bear the burden of proof.
The process of applying the Precautionary Principle must be open, informed and democratic and must include potentially affected parties. It must also involve an examination of the full range of alternatives, including no action”.

Source: http://www.sehn.org/wing.html

The short version of the above statement is if there is a belief that an activity or product is perceived to be harmful to the environment or human health, that activity or product should be banned until it can be proved that that product or activity is “deemed safe”.

There are federal, state and local governments that are adopting precautionary statements as part of health or environmental legislation or these government bodies using precautionary statements as an informal, unwritten policy.

As one could see that the Precautionary Principle is an important tool for environmentalist since proof of harm is not needed in order for government bodies to ban products.

As Cass Sunstein, the current director of the Office of Information and Regulatory Affairs in the Obama administration stated “Yet the precautionary principle, for all its rhetorical appeal, is deeply incoherent. It is of course true that we should take precautions against some speculative dangers. But there are always risks on both sides of a decision; inaction can bring danger, but so can action. Precautions, in other words, themselves create risks - and hence the principle bans what it simultaneously requires.”

The link shown below is an article written by Cass Sunstein regarding his thoughts on the Precautionary Principle:

The Paralyzing Principle-Cass Sunstein

We encourage anyone to investigate and dispute the findings contained on this website.

Coal Tar Pavement Sealer
Polycyclic Aromatic Hydrocarbons in Coal Tar Sealers
Misconceptions About Pahs in Tar Sealers