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Lawsuit: Driveway sealant leached carcinogens into Minnesota ponds

Can eight Minnesota cities make these companies pay for polluting their ponds?

Can eight Minnesota cities make these companies pay for polluting their ponds? YouTube

It’s not summer in the suburbs until you see at least one dude in a sleeveless shirt spreading lustrous black goop over somebody’s driveway. The hot, dry season means it’s sealant time for Minnesotan pavement -- a chance to re-apply protection against the rain, snow, and ice yet to come.

But as it turns out, eight suburbs in the Twin Cities area -- Bloomington, Burnsville, Eden Prairie, Golden Valley, Maple Grove, Minnetonka, White Bear Lake, and, most recently, Eagan -- now have concerns about that driveway sealant. So much so, in fact, that they’ve all filed separate lawsuits against the companies that sold them the goopy black stuff – seven companies including Koppers Inc. and the alliterative Coopers Creek Chemical Corporation -- in the last month.

The issue isn’t the quality of the sealant. It’s the high concentrations of chemicals inside the sealant: polycyclic aromatic hydrocarbons, or PAHs for short. PAHs are “ubiquitous in the environment,” according to the Minnesota Pollution Control Agency. Heck, they’re what make the char on a grilled hotdog taste so good. But in high doses, they’re “generally carcinogenic” and best to avoid. That’s why coal tar sealants have been banned in our state since 2014.

But that doesn’t mean these cities’ problems ended in 2014. According to Eagan’s complaint, these coal tar sealants, once applied to the city’s suburban driveways, started to break down under the assault of wind and rain, and washed straight into the city’s many stormwater ponds.

That’s not normally a big deal -- that’s what these ponds are for. They’re designed to be filters for the city’s’ runoff, so nothing too toxic can flow into local lakes and streams. The problem is that this isn’t just normal pollutive chemical scum; it’s carcinogenic pollutive chemical scum, and that requires a much more careful, expensive cleanup process -- sometimes costing twice or even 10 times as much as usual.

“[The sediment] contains contaminants that require it to be deposited at a regulated landfill,” Eagan Public Works Director Russ Matthys says. “Every five years, we’re probably going to have an extra $150,000 of costs.”

These sealant companies, the cities allege, “knew or should have known” the PAHs in their products would wreak mayhem on the environment, so they should be responsible for cleaning them up. Matthys says the cities’ attorneys think they have a pretty good shot at winning.

“They either have to have the taxpayers burdened with that cost, or the polluter,” lead attorney Robin Greenwald told MPR. Her firm, New York-based Weitz & Luxenberg, is representing the cities.

Koppers, meanwhile, isn’t taking this lying down. A spokesperson sent a statement saying the company “does not believe there is merit to these claims and intends to vigorously defend these matters.”

In the meantime, the ponds in eight Minnesota cities will continue to contain PAHs in their scummy waters, and cities will continue to dredge them -- hoping they can get someone else to pay for it.