Once again the sealcoating industry is faced with what appears on the surface to be specious allegations concerning refined coal tar-based sealer. These new allegations - concerning dust vacuumed from first floor apartments near parking lots - stem from Austin, TX, which fired the initial "ban coal tar" shot in 2006 with claims that coal tar-based sealer damaged aquatic life in Barton Creek.
This topic is so complex and confusing, and there is so much misinformation out there, that it is difficult to know where to begin when combating these studies. So it's a good thing the sealcoating industry has the Pavement Coatings Technology Council (PCTC) out front, trying to clarify and educate the people trying their best to make regulatory decisions based on these studies. We are certainly not scientists and all we've done is read the studies and talked with the PCTC folks, but even to us a few things become clear.
First, the studies confuse, either deliberately or because they don't know any better, crude coal tar and refined coal tar. There's a huge difference between the two, and refined coal tar has been used in this and other industries for 60 years without any link to serious health issues.
Second, follow-up research to the initial Barton Creek study after the coal tar sealer ban showed no difference in PAH levels in the same pool. Since the material was banned why was there no decline in PAHs? PAHs should have declined if coal tar was the main culprit.
Third, this is an industry-wide issue, not an issue limited to refined coal tar-based sealer. There is no denying refined coal tar-based sealer contains minute levels of PAHs. There is also no denying that asphalt emulsion-based sealer also contains minute levels of PAHs. It seems reasonable that if these Austin folks are successful in banning one material they will soon move on to the other.
So this is an "All for One, One for All" issue. It's a moment when all those in the sealcoating industry need to have one another's back.