Metro Cities Sue Pavement Sealant Makers for Alleged Stormwater Retention Pond Contamination

Eight Twin Cities suburbs recently filed identical suits in Minnesota federal court alleging that several companies’ refined coal tar products used in pavement sealants have contaminated city ponds.  The cities claim that the pavement sealants are contaminated with high levels of Polycyclic Aromatic Hydrocarbons (“PAHs”).  According to the lawsuits, as the pavement sealants degrade, fine particles of the refined coal tar products migrate into the environment via wind and rain and accumulate in city stormwater retention ponds.

The plaintiffs contend that sediment contaminated with high levels of PAHs requires testing, special handling and disposal in connection with periodic dredging of the retention ponds. The lawsuits allege that this has greatly increased costs for managing stormwater infrastructure.  Minnesota pollution officials have estimated potential costs of more than $1 billion to clean out Twin Cities metro-area ponds, according to the Twin Cities Pioneer Press.¹

In 2014, Minnesota became the second state to ban the use and sale of pavement sealants using refined coal tar. Prior to the ban, refined coal tar-based sealants were commonly applied to asphalt driveways and parking lots. The plaintiff cities claim adequate substitutes exist and that defendants knew or should have known of the links between the use of refined coal tar in sealants and the rise in PAH contamination in urban lakes and ponds.

The eight lawsuits are captioned as follows:

• City of Burnsville, Minnesota v. Koppers Inc. et al., Court File No. 18-CV-03495-MJD-DTS;
• City of Eden Prairie v. Koppers Inc. et al., Court File No. 18-CV-03496-DWF-KMM;
• City of Maple Grove v. Koppers Inc. et al., Court File No. 18-CV-03497-NEB-BRT;
• City of White Bear Lake v. Koppers Inc. et al., 18-CV-03498-JNE-KMM;
• City of Minnetonka v. Koppers Inc. et al., 18-CV-03501-NEB-SER;
• City of Bloomington v. Koppers Inc. et al., 18-CV-03503-DWF-ECW;
• City of Golden Valley v. Koppers Inc. et al., 18-CV-03509-JRT-ECW; and
• City of Eagan, Minnesota v. Koppers Inc. et al., 19-CV-00058-MJD-DTS.

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