Decoding the Coal Tar Sealant-to-Cancer Connection

A recent scientific journal came out with little attention or really no media coverage at all. While there may be a variety of reasons why, my hunch is that part of the reason is that it contains some pretty complex and difficult concepts to communicate. Well I thought I would try to decipher a bit of that for you here.

The first task at making this a little more lay-friendly was to redo the above graph using data from the report. The essence of the paper is really contained in this graph. If you take your time to understand it, these are the key points:

1. There is some cancer risk from ingestion from background PAH (polycyclic aromatic hydrocarbons) sources that we get from food and the environment, but it is in a risk range that the EPA would review on a case-by-case basis. This is why we frequently hear public service announcements to minimize eating grilled meat and exposure to tobacco smoke (incidental 2nd hand if you will).
2. Any exposure scenario to from the proximity to coal tar sealed asphalt puts the risk into the zone of "desired remediation" or as stated previously "federally unacceptable."
3. Most exposure comes from coal tar sealant contaminated soil instead of indoor dust.
4. Early childhood exposure is most troubling, but so is also in the red zone is a lifetime of exposure or even just exposure during adulthood.

Renewed Calls For Statewide Ban of Coal Tar Sealants in Minnesota

The Rice Creek Watershed District is shown in the colored areas above.

In spite of efforts throughout the State of Minnesota, calls continue for the uniform outlaw of the use of coal tar pavement sealcoats. For example in November a watershed management of group covering 4 urban and rural counties called for "a state-wide approach" which would "provide consistency across jurisdictions in the state" and "in order to protect, restore and preserve the quality of its waters." The Rice Creek Watershed District (RCWD) unanimously requested action to bring about a state ban. While Minnesota has the most community bans in the US, unfortunately the bans in Minnesota make up just about 17% of the State's population.

40 Brave Minnesota Sealant Applicators Take the Pledge to be Coal Tar Free

This just in from the Minnesota Pollution Control Agency (MPCA) who is working to phase out the use of coal tar sealants both by encouraging bans of the harmful substance as well as asking applicators to voluntarily stop its use. I wanted to give credit to those applicators who have made this pledge by mentioning them here. This is the first time a group of applicators have stood up and taken such a position. 

Who will be the next to step up? 

After this list is an email from the MPCA with additional information and links.

Two More Minnesota Communities Pass Bans Last Night

Last night two Minnesota communities, Shorewood and Woodland, passed their final ordinance readings and enacted the 27th and 28th municipal bans of coal tar pavement products in the state. Both communities are situated on the southern shore of Lake Minnetonka.

Woodland's ban includes the prohibition to both apply and sell coal tar sealers.

Tales From the Front: What Coal Tar Contractors are Telling Their Customers

With bans popping up all over the nation, I think we are beyond the "brewing" stage!

This is a false statement. Yes you don't have a dog in this hunt. You have TWO: Pride & Money. If what the environmentalists have been saying is true, then your pride may resist that for 32 years your efforts, which may be innocent, have been responsible for environmental and economic harm.

This is a false statement. Really? Facts? Many of these points are based in "myths" not facts. Unbiased? Since when is industry-sponsored research unbiased? Industry-hired research does not meet the standard as set by the National Academy of Sciences concerning a conflict of interest (Conflict of interest is defined as any financial or other interest which conflicts with the service of an individual because it could impair the individual's objectivity...).

This is a concealment. Just because someone manufacturers both kinds of products does not make them unbiased. Sealant manufacturers may be biased for a number of reasons including equipment infrastructure, quality of their products, liability, supply chain, profitability, etc..  

This is a concealment and means to imply that there is limited information on this issue. There are close to 25 scientific publications that include coal tar sealants and they have been done by local agencies, universities, the USGS, the EPA, states, and a division of the Centers for Disease Control. There were just 2 studies 7 years ago, but much has changed since then. Links and abstracts of most of the studies can be found at this post on this site: Human Health, Coal Tar Sealants, & PAHs: the State of the Science. Just click the highlighted text to go to this page.

I did a post about that entitled, The Myth of Flawed USGS Studies which traces the origin of these mis-statements. Just click the highlighted text to go to this page.

While it is true that Springfield did vote against a ban in 2010, here's an update. The University of Missouri and the City of Springfield did a joint study and found coal tar sealants are a pervasive stream pollutant there. The ban may be revisited as a result.

This is a concealment. The developer had this experience more than a decade ago in the infancy of asphalt-based sealer development. That's like saying "I'm not going to get one of those cell phones because I used one 20 years ago and it weighed over 10 pounds!"

While people may disagree on what a "rush" is, but dozens of studies, by multiple scientists, throughout the nation, over nearly a decade now, is no "rush" to judgment in my opinion.

This same councilwoman recently said, “I think this (University of Missouri Study) makes it clear that coal tar is the problem,” she said. “Now the question becomes, what are we gonna do about it?"

Where was this "proven?" Asphalt-based sealers and coal tar sealants vary dramatically in quality and price. I have seen asphalt-based sealcoat outperform, in all aspects, coal tar sealants. Check out the post associated with this comment.

Coal tar shampoo is a common dodge by the industry. There is a huge difference between a medicated product used in a controlled manner versus a pavement product that as it cures and wears indiscriminately exposes children, adults and the environment.

I recognize you are busy but have you actually read the any of the studies that show this product harms aquatic organisms? If you have read them, what makes them lack credibility other than they reach a conclusion that you do not support? 

This is a concealment. The active ingredient in coal tar sealants is coal tar pitch, which has something like a serial code definition called a "chemical abstract service" or CAS number. For coal tar pitch it is CAS No: 65996-93-2. The International Agency for Research on Cancer (IARC) states the following:

• Evidence for carcinogenicity to humans (sufficient)
• Evidence for carcinogenicity to animals (sufficient)
• Summary evidence: Coal-tars are carcinogenic to humans

This is a false statement. Because of the exceptional concentration of PAH in coal tar sealants compared to asphalt-based sealers, an asphalt sealant would have to wear off and be re-applied every day to be equivalent to the potency of a coal tar sealer.

Since asphalt sealers are so much less harmful, this is extremely unlikely.

Did you know that studies have shown that coal tar sealers degrade asphalt and that it isn't recommended by the leading association for pavement quality in the United States?

Are we willing to attract customers by putting hazardous material on our properties? Would they be so excited to go to these commercial businesses if they knew what is on the parking lot? Today's asphalt-based sealant stays black for the life of the product. However with as much as 30% of our urban surfaces heat-absorbing black, perhaps it's time for us to move beyond the black paving aesthetic.

A letter is being circulated around among contractors that continue to use coal tar sealants. They use it to convince their customers to continue to use this toxic product.  Isn't it amazing that this was the most read article among sealcoating contractors in 2012! 

It was written from a contractor to his client to assure the client that all this talk about coal tar sealant pollution is bunk. In my opinion this is the chaos that is created when our regulatory agencies don't step up and show leadership that their own research shows is a problem. Until that happens, we will continue to challenge flabby thinking on this issue.

When I first read this letter on the Paveman Pro website, I wrote a response to be published on this website, but the editor felt that my response was too personal and would not publish it.  My intent was to be respectful but straightforward. Apparently it was too straightforward!

Well I guess that is what a blog is for! My intent is not to make personal attacks, but to show the fallacy of the arguments made.

If you don't want to wade into this point-by-point, then let's here's my summary. This letter is full of the following:

• Exaggerations:
• Understatements:
• Concealments:
• Equivocations (the use of a vague expressions, especially in order to mislead):
• False statements:

It's a pretty sad reality if this is what it takes to sell your product.