An environmental advocacy group filed a class-action lawsuit on Thursday against a coke production plant in Monessen, Westmoreland County, for over 225 pollution violations.

PennEnvironment, with the help of outside attorneys, is suing steel company ArcelorMittal for violating the United States’ Environmental Protection Agency’s Clean Air Act. PennEnvironment issued an intent to sue letter to ArcelorMittal 60 days ago.

The plant exceeded its emission limits for sulfur dioxide, hydrogen sulfide and particulate matter between April 2014 and June 2015, according to National Environmental Law Center attorney Heather Govern.

The violations have caused health problems for local residents, Govern alleges.

“There’s quite a bit of suffering going on,” she said, “from respiratory problems, headaches from these noxious fumes and waves of soot and black dust that continues to rain down on the homes and backyards of many of the citizens living in towns surrounding the plant.”

PennEnvironment contacted the Pennsylvania Department of Environmental Protection and the EPA regarding the coke plant. Both agree there are “improvements to be made” at the plant, according to Govern.

Mary Beth Holdford, a spokesperson for ArcelorMittal, said the company has not yet reviewed the lawsuit.

“ArcelorMittal is disappointed that PennEnvironment representatives feel it is necessary to file a complaint as we believe U.S. EPA and PADEP are well-prepared to address the regulatory issues,” Holdford said in a written statement. “Numerous enhancements and investments to the facility made over the last several months have resulted in improved environmental performance; our goal is to maintain full compliance.”

Viktoryia Maroz, a plaintiff in the case, is a resident of Donora, about a mile from the coke plant. She said that her community has encountered health problems as a result of the pollution.

“On a daily basis the odors and pollution from the Monessen coke plant are so terrible that I experience extreme headaches, fatigue and gagging,” Maroz said. “The odors can be so strong in and around my house that I’m woken by them in the middle of the night.”

Maroz said she can no longer live in the conditions she lives in now.

“Just by breathing I’m being poisoned, my neighbors are being poisoned and everyone living in towns near this plant are being poisoned by ArcelorMittal,” she said.

Govern said that PennEnvironment and the other plaintiffs are willing to hold “good faith” talks with ArcelorMittal to see if the matter “can be resolved without litigation,” but a date for such talks not been scheduled.