If you use refined coal tar sealers and have recently received resistance from new or existing customers regarding their safety, you may not have immediate answers to help you explain the industry position. In fact, some contractors have switched away from using RCT sealers all together under the pretense of being “green” because of recent articles and media hype.

But as Dan Browne of the Asphalt Adviser pointed out in a recent blog post, “If you’re considering a switch based on recent articles, keep in mind that the USGS studies in Austin have been proven flawed and none of the cities that have banned coal tar have done their own studies. There has never been a documented case of cancer resulting from the use of Refined Coal Tar Sealers. RCT Sealers are unjustly confused in the USGS studies with Crude Coal Tar – it’s not the same material.”

Thankfully, more and more contractors are becoming aware of the flaws in these studies and are beginning to fight these uninformed assumptions by educating themselves, prospects and long term customers.

One such contractor, Gerry Signs of Asphalt Enterprises (Atlanta, GA) and longtime industry veteran, has begun doing just that as the issue has surfaced among property owners and managers. He recently shared a letter he has put together for customers and prospects that educates them on the long held industry position — that Refined Coal Tar Sealers are safe.

Graciously, Gerry has allowed us to reprint the letter here so that fellow contractors will be encouraged to educate themselves and their customers with the hard facts. You are free to use this letter as a template for your own personal use, replacing your company information where applicable.

As a result of this well written and researched letter, Gerry’s customer decided to stay with Refined Coal Tar Sealers for their properties.


Dear John,

I know there is somewhat of a controversy brewing regarding the safety of coal tar sealer in relation to the environment and humans, and this is not the first time I’ve had to address this issue.  Let me start by stating that I have been in this industry since 1980, and started Asphalt Enterprises in 1983.  There aren’t too many contractors in the United States who have been responsible for more gallons of coal tar sealer applied than myself, and we are the number one applicator in the Atlanta area, and have been for years.  Let me also state that I have no dog in this fight, that is, coal tar sealer vs. asphalt emulsion sealer, since we can apply either material, and have applied a fair amount of asphalt emulsion sealer in the past. What I like to look at are the facts, based on unbiased, untainted scientific studies, and also common sense and my years of experience.  Also as a side note, all pavement coatings manufactureres produce both coal tar sealer and asphalt emulsion sealer, so actually their studies are also unbiased.  They are just convinced, and rightfully so, that coal tar sealer is a superior pavement coating.

Environmentalists recently have upped their efforts on having coal tar sealer banned, based mainly on the results of two studies, one in Austin, Texas, and the other performed by the U.S. Geological Survey.  Unfortunately for the environmentalists, both studies have been proven to be flawed by independent researchers.  Please visit the following links for a more detailed explanation of the flawed studies.





In 2010, Springfield, Missouri tried to have a ban placed on coal tar sealer, and put it in front of the city council for a vote.  Below is a link to a letter submitted by a property developer who owns shopping centers in Missouri, trying to convince the city council to reject the ban.  This developer had very positive experiences with coal tar sealer, and very negative experiences with asphalt emulsion sealer (I’ll touch on that below). By the way, the ban was rejected.


John, as you can see there has been a huge “rush to judgement” regarding the banning of coal tar sealer.  One of the city council members who voted against the ban made very good sense when she stated that she heard evidence from Phd’s stating that coal tar sealer was harmful, and she heard evidence from Phd’s stating that it was not harmful and they provided the research to prove it was not harmful.  In the end she said there was no compelling evidence to believe that coal tar was harmful.

Let me just take a minute to explain the difference between coal tar sealer and asphalt emulsions. Coal tar sealer has been around for over 60 years, and coal tar was chosen over asphalt emulsion as a better raw material based on its ability to prevent the intrusion of gas, oil, and other pretoleum products from damaging the pavement, and the very hard film that coal tar forms over the pavement, making it very durable to heavy traffic.  Asphalt emulsions are used as a raw material in sealer only as a substitute, in areas where coal tar is not available , and has proven to be an inferior substitute. Asphalt emulsion sealers only last a couple of years, only one coat can be applied in a day, wash out areas are very common.

In closing I just want to state some facts regarding coal tar:

–  The FDA has approved coal tar for decades as a base ingredient for skin creams and shampoos that fight certain skin conditions.  It is very odd that the FDA would approve coal tar to be applied to the skin and scalp IF it was harmful.  The amount of PAH’s produced by these items is far higher than that in coal tar sealer.  Not sure why the environmentalists aren’t fighting the FDA and pharmacuetical companies to have coal tar banned from skin creams and shampoos.  This fact ALONE should dispell any belief that coal tar sealer is harmful.

– In the over 60 years that coal tar sealer has been used, there is no study that shows any harmful affects to humans or animal life attributed to coal tar sealer.

– Coal tar sealer is NOT and has NEVER been classified as a hazardous material by the EPA.

– Asphalt emulsions also produce PAH’s, and in fact, since asphalt emulsion wears faster than coal tar sealer, these PAH’s are released into the storm drains and streams at a faster rate. Also PAH’s in asphalt emulsions are lighter than those of coal tar sealer, thus they will stay afloat and wash further down stream, as opposed to coal tar PAH’s which will fall rapidly, attaching to sediments, causing zero affect on PAH levels in the water.  Other producers of PAH’s include, tire wear residue, motor oil drippings, car exhaust, hot mix asphalt, jet exhaust, roof shingles, even cigarettes, outdoor grills, volcanos, and forest fires and other outdoor burning, even wood burning in home fireplaces.

I’m afraid that the if the environmentalists are successful at banning coal tar sealer, their next step will be to ban asphalt emulsion sealer based on what I stated above.  What they don’t realize is, banning sealants in the long run will have a much greater affect on the environment and natural resources.  Pavement life will be decreased dramatically, requiring increased levels of asphalt replacement, overlayments, and total replacements.  This will require more crude oil to manufacture the asphalt, more rock extracted from our rock quarries, more fuel to manufacture asphalt and raw materials, not to mention the performance of this work. Most asphalt pavements will need to be replaced within 10 years.  As an owner and investor in shopping centers, this will also place a financial burden on companies like yours and their investors, not the mention the lack of “curb appeal” which attracts customers to a freshly sealed and well maintained parking lot.

With my 32 years working in the sealcoating and paving industry, I have not seen any credible studies showing that coal tar sealer is harmful to humans or the environment.  And without hesitation, if I saw any compelling, unbiased study showing it was harmful, I would discontinue it’s use within my company immediately.

Thank you John for taking the time to read this, and hopefully it will make a change on how coal tar sealer is viewed.


Gerry L. Signs
Asphalt Enterprises, Inc.

Gerry Signs is the Owner President of Asphalt Enterprises, an Atlanta Paving Company, that has provided asphalt paving and maintenance services to the Metro Atlanta area for over 30 years.