The Sticky Truth About Coal Tar Contamination

Episode Transcript

Mollie (Host)
Welcome to {Brief}ly Speaking, the SEH podcast that cuts straight to the chase. We'll tackle big topics in architecture, engineering, and construction with quick expert insights. No fluff, just the essentials, all in a few minutes. Let's dive in. Today we're discussing the hidden, sticky, toxic mess known as coal tar. You might not see it, but it's lurking beneath our parks, rivers, and old industrial sites, quietly holding on to a century's worth of pollution. It might even be closer to home than you think. And here today to help us break it down is someone who's been helping communities tackle this challenge head on. He's a professional engineer, a LEED-accredited professional, and Envision-certified trainer, bringing both technical expertise and a sustainability mindset to projects. Tom Ennis, welcome to {Brief}ly Speaking.

Tom (Guest)
Thank you, Mollie. Great to be here.

Mollie (Host)
So to start us off, can you break down what coal tar actually is? Where does it usually show up in communities? You know, we hear about PFAS, we hear about lead and copper. This kind of feels along those same lines, but it doesn't have that same recognition. So tell us a little bit about it.

Tom (Guest)
Okay, well, coal tar has a long history. It's a byproduct of purifying coal. So when you heat up coal, in the old days, they would heat up coal to get gas out of it because they didn't have natural gas, and they'd have this sticky stuff left over. And everybody, a smart person would figure out what do we do with that sticky stuff. Sometimes they put it on roads. Sometimes they weatherproof ships. Tar heel state is tar for ships for keeping waterproofed. And then also they made these dyes. And in the 20th century, 21st century, people started putting on asphalt to purify and beautify asphalt parking lots. So they look pretty longer than when they normally turn gray. So coal tar in itself has been around a long time, has a long history of study, both from a useful product. The concern was during World War I, the Germans were better at purifying and getting products out of coal tar than any of the opponents of Germany. And so that coal tar was a big pivotal part of World War I, crazy as that is.

Mollie (Host)
So I'm assuming just by the name that it's just blacktop, essentially black tar?

Tom (Guest)
Well, kind of. It's one of those that makes it difficult describing this because There's asphalt that your normal roads look like and that's comes from petroleum. It's petroleum. It's left over from refining gasoline and oil and that sort of thing. Coal tar is a byproduct of refining coal. So they both look black. They have different chemical properties and different physical properties as well.

Mollie (Host)
We mentioned that, you know, this is quietly holding on to a century's worth of pollution. What are the risks that we're talking about once it's present, especially when it comes to the environment and public health?

Tom (Guest)
I've been looking at this for over 20 years now, and every time I read more, there's more to learn. There is a long-term study of exposure to the chemicals that are in coal tar are called PAHs, polycyclic aromatic hydrocarbons. They look like a five-sided bathroom tile. And that's what a PAH is. And they're all different. There's a whole family of them. They're all different, connected in different patterns and have different chemical characteristics. But all these PAHs are out there. And what we found out, the first cancer was actually isolated in a laboratory by some Japanese researchers, in 1917, something like that. And they figured out that by just putting coal tar on rabbit's ears for less than three weeks, most of them had cancer. And so even today, if you want to give lab animals cancer quickly, you use coal tar. And that very same product is on playgrounds, parking lots, and driveways in the United States.

Mollie (Host)
So obviously that's alarming. We don't want that on parking lots, playgrounds, near anyone, but especially kids. So for communities that are now like, oh no, is this a concern for us? How can they go about identifying it? What are the first steps to addressing it?

Tom (Guest)
The good news is that since 2007, if whatever's on your parking lot or driveway was bought at a home improvement store, it hasn't been available for sale since 2007 in the United States, or at most big-box stores. So if you've got some leftover handyman special, it's probably not coal tar. But there are some ways to test. There's a field test that a buddy and I developed that you just use stuff from a home improvement store, and you can test it yourself. We call it a coffee tea test. You put it in the solvent, and if it looks like coffee, it's asphalt, if it looks like tea, it's coal tar. And researchers have used it all over the country to determine what you have. It's much, it's a quick field test and if you're going to, you know, have a legal action or something like that, you send it to a lab. But for a screening test, that's what we developed.

Mollie (Host)
So post 2007, you're in the clear. But pre, we should probably be testing.

Tom (Guest)
Right. And it's unfortunately more complicated than that because if you just parking lot I just walked across here, coal tar is still legal in this community in West Texas. And I can tell by looking at it that I'm walking across a coal tar-sealed surface. So it's still present, it's still being used. The retail market only represents about 10% of all the use. So most of it is actually done at by commercial applicators. So the fact that it's not in the stores means hooray, only 10% isn't being done. And so now, folks in different states, you can find out. There's a website called Coal Tar Free America that I actually happen to run, but it actually has a list of bans where they are in the country. You find out if it's legal in your community or not. And it's been banned in over 7 states and over 100 communities in the United States.

Mollie (Host)
Let's say that a community is, they're redoing a project, they're starting to look into this. They do their testing, the coffee tea testing, like you had talked about, and they think that it's col tar, and they call you, Tom Ennis. What would be your process to kind of help them get started, some options that they have to move forward with remediation?

Tom (Guest)
the first strategy on a remediation is stop doing the stuff that's polluting your community. So start, encourage you need to do that voluntarily or by permit or by outright regulation. So stop that. The other thing is if it's in sensitive areas where people are exposed, you can remove it. It's a mechanical process to just basically it's like refinishing a wood floor. You just grind off the top layer of asphalt and then you recycle or you throw that away is how you take care of that. The other challenge that communities need to continue to be aware of is when the stuff wears off, it doesn't just magically disappear. Like as you said, it lasts over 100 years. If it wears off and the tires may drag it to another parking lot, it may get washed off and it may be in the soil right adjacent to the parking lot. And I also was co-author of a paper where we actually found that it's in the dust in homes. If you have that stuff on your driveway or your parking lot, you're dragging it into your homes and it's a significant exposure to your children when they crawl around on the carpet or on the floor because they're hand to mouth, they're eating accidentally all the time, as you well know.

Mollie (Host)
If they call you again, like we were talking about. They call you and they are like, "hey, what are our options here?" What are the replacements? Just, I mean, you mentioned shaving it off, cleaning it up. What other stuff could they put down that would be a better environmental sustainable option?

Tom (Guest)
Right. There are products out there that are 1000 times less toxic that perform just wonderfully. So they protect the asphalt. They make it look nice and black and new. I tested over a dozen products on the market in laboratory certified laboratory testing that shows that they're low toxicity products.

Mollie (Host)
Good. So there's options. We have better options. I know in a previous question you had mentioned about how this isn't a stationary problem. It travels, it gets put in streams, it gets taken into houses. So I'm assuming it's a little bit of a longer cleanup process. So after we go through and remove it, replace it with something better, what happens next? What does long-term monitoring or follow-up typically involve?

Tom (Guest)
If you scrape off that top layer, it doesn't really penetrate beyond 1/4 of an inch or whatever below the surface. So in most situations, that takes care of the pavement problem. If for the proactive individual, if it's been going on a long time, they need to test their soil and find out because I've seen situations where just normal parking lot use is I know of a school that was going into a place that had a parking lot and they did a whole environmental analysis of the school grounds and they found out that the soil was contaminated and it wasn't from what was happening inside the building. It was just the parking lot contaminated the soil near the parking lot so much that they had to dig it up before they would put a school there.

Mollie (Host)
Long investment, it sounds like.

Tom (Guest)
Well, it's shovels and hauling things to a landfill is really relatively inexpensive. And it's one of those strange products that I've actually done some number calculating on. And it's like the what it's economic good if you all say that whatever its economic value, it doesn't even reach its damage is greater than its value by just by a simple cleanup, let alone health or environmental degradation.

Mollie (Host)
I mean, it feels like a really, quote-unquote, easy way to remove something that's so harmful. I mean, if we knew that was anywhere else, I feel like it would be a no-brainer. 

Tom (Guest)
And I've heard, I made a montage once of all the legislators who've said, this is just common sense. This is just common-sense legislation, common-sense ordinance, because that's just what it is. You know, you have high concentrations; it can hurt the environment and people. We don't need to use it. Let's stop doing that. People always ask me, where's the EPA in this? The EPA is not one voice. You know, there are EPA-sponsored webinars on coal tar sealants on, you know, coal tar on pavements that it's a problem. They've sponsored those. They've sponsored research. They have published information brochures to let the public know. And in their own research, they say, you know, the most appropriate thing for a community to do themselves is to ban it. That's their recommendation. The American Medical Association has said we support removing this from the marketplace. So that's really big. They don't do that for every old chemical or every product that's out there. And I would say that's something people should understand. There is over 50 research papers supporting this effort, all different angles, all different places, European researchers, US, Canadian, Chinese, everybody sees the same thing. And the researcher who from MD Anderson Cancer Clinic who testified Austin, Texas was the first to ban that in 2005. She said, this stuff is just nothing but buckets of carcinogens. That's a cancer researchers description of a product.

Mollie (Host)
Well, my final question here is if a community even suspects that they might be dealing with coal tar, how can they reach out to you? What are the steps to get started working with you, Tom?

Tom (Guest)
You can reach me at tennis is my email address, tennis@sehinc.com. And that way we could start the conversation. It's the other thing I can help do is if a community passes a ban, I can help them train their staff on how to do that testing. as well as how to enforce it, what to look for. Because once you learn this, you'll never cross a parking lot in the same way. You'll look to see is that coal tar sealed or not or whatever. Does it have the telltale signs of seal coat?

Mollie (Host)
I really appreciate you walking us through this. It's a topic that doesn't always get the spotlight, but it clearly deserves it. Hopefully this helps communities feel a little more informed and empowered to take the first step. So Tom, thank you so much for talking through coal tar. And this was our episode of {Brief}ly Speaking.

Tom (Guest)
Thanks for having me.