Koppers Unable to Shed Suit Over Pollution From Illinois Plant

The operator of an Illinois coal tar plant must continue to defend a proposed class action in federal district court alleging the emissions of “noxious odors into the ambient air” creates a public nuisance in violation of state law.

Judge Jorge Alonso of the US District Court in the Northern District of Illinois found Monday that lead plaintiff Colin Petrus plausibly alleged state law nuisance claims because the odors from Koppers Inc.‘s plant interfered with his and other potential class members’ enjoyment of their property and right to clean air.

“Noxious odor created by the coal tar plant plausibly invaded Plaintiff’s use and enjoyment of property and plausibly interfered with Plaintiff’s right to clean air because it was strong enough to prevent Plaintiff from using his porch, his yard, and from going on walks with his children,” Alonso said.

Based on geographical proximity to the residential area—a suburb of Chicago—and that it was reasonably foreseeable that pollution from the plant could affect that area, the court also found Koppers had a duty of care to support Petrus’s negligence claim.

Further, the global chemical and materials company received multiple notices of violation from the Illinois Environmental Protection Agency addressing its management of air pollution from its 36-acre coal tar plant. Therefore, Petrus plausibly alleged a breach of that duty, the court held.

Petrus is represented by Liddle Sheets Coulson PC and Marshall P. Whalley & Associates PC. Kirkland & Ellis LLP represented Koppers.

The case is Petrus v. Koppers, Inc., 2025 BL 216620, N.D. Ill., No. 1:24-cv-06872, 6/23/25.