Minnesota Cities Sue Refiners Over Storm Water Pond Pollution

Seven Minnesota cities have filed suit against several large chemical refiners over contamination of hundreds of storm water ponds caused by a black sealant sprayed on parking lots, driveways and playgrounds. While the pavement sealants now are banned in Minnesota, the cities argue that the sealants contained high levels of a carcinogenic chemical that spread into soils and water. Separate lawsuits seek to recover projected costs associated with cleaning up storm water ponds and removing contaminated waste.

According to The Minneapolis Star Tribune, officials in Burnsville, Minn., one of the plaintiff cities, estimate that up to a third of the city’s more than 270 storm water retention ponds have been contaminated by polycyclic aromatic hydrocarbons (PAHs) found in the sealant and require sediment to be hauled to landfills with costs exceeding $150,000 for larger ponds.

Koppers Inc., one of the chemical manufacturers under fire in the suit, has said the suit is groundless, as reported by Fox 9.

“Koppers does not believe there is merit to these claims and intends to vigorously defend these matters,” a written statement said.

However, the plaintiff cities argue that the increased costs of testing and cleaning contaminated storm water ponds affected by PAH leaves the cities less money for regular maintenance. This may leave shallower ponds less effective at preventing contaminant-laden storm water runoff from entering waterways.

“If we can’t clean them out as quickly, then phosphorus and other contaminants will continue to bypass the ponds,” said Ryan Peterson, Burnsville’s public works director. “The result will be decreased surface water quality of the lakes and streams that people love.”