A fresh coat of coal tar-based sealant can make dingy driveways, parking lots and other paved surfaces look brand new. But the thick, black liquid is also full of polycyclic aromatic hydrocarbons, or PAHs, which can kill aquatic life and cause cancer in humans.
Communities that have filed lawsuits say the makers of coal tar sealants knew their products were dangerous and would contaminate the environment but sold them anyway. The cities are suing to have the coal tar refiners cover the costs of monitoring and cleaning up local waterways.
Cleaning up PAH-contaminated water is intensive and expensive. In the Twin Cities area alone, projected cleanup costs could approach several billion dollars.
Minnesota Cities Sue Coal Tar Refiners
The state of Minnesota passed a bill banning the use of coal tar-based sealants in 2013, and it’s been illegal to sell or use the controversial product in the state since 2014. But years of prior use have caused extensive water contamination.
A 2014 study in the Archives of Environmental Contamination and Toxicology found high concentrations of PAHs in more than a dozen stormwater ponds in the Minneapolis-St. Paul metropolitan area. The study, which was conducted by the Minnesota Pollution Control Agency, reported that coal tar-based sealant runoff and dust contributed to more than 67 percent of the pollution.
The PAH levels were high enough in nine ponds to pose a risk to humans, according to the study. Because of the potential risk to humans, the Minnesota Pollution Control Agency concluded that the contaminated sediment in those ponds would have to be dug up and hauled off to landfills.
In January 2019, eight cities in the Twin Cities area filed suit in U.S. District Court in Minneapolis against several large chemical refiners over the pollution. The cities are seeking to recover the costs of cleaning up the ponds and disposing of the hazardous waste. The group of cities that are suing include: Bloomington, Burnsville, Eagan, Eden Prairie, Golden Valley, Maple Grove, Minnetonka and White Bear Lake.
Among the defendants named in the case is Koppers Inc., a Pittsburgh-based company that manufactures pavement sealants from coal tar. The company told Minnesota Public Radio that the claims in the lawsuits are without merit and it will fight them. Other defendants named in the lawsuits include: Coopers Creed Chemical Corporation, Lone Star Specialty Products, Rain Carbon Holdings LLC, Rain Carbon Inc., Ruetgers Canada Inc. and Stella-Jones Corp.
Cleaning up PAH-contaminated water is not cheap. After the toxic material is dredged from a pond, it requires a special type of disposal. It must be hauled away to authorized landfills where it won’t seep into soil and water.
Hauling away heavily contaminated sediment can cost an extra $75,000 to $125,000 per body of water, and cleaning up all the ponds in the Minneapolis region could cost upwards of $1 billion, according to the Pioneer Press.
The lawsuits contend that the companies who manufactured the toxic materials should bear the expense, not taxpayers.
Costs could run even higher, however, because no one knows exactly how many ponds are affected. According to the City of Bloomington’s website, study and sampling have been limited, but anywhere from one-fifth to one half of all ponds may be contaminated with PAHs.
While the lawsuits filed by the cities in Minnesota are the first of their kind, they may not be the last. Sealcoating with coal-based products is a widespread practice east of the Mississippi and more cities may take legal action as contamination is uncovered and cleanup costs pile up.
17 Cited Research Articles
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