Citizens for Pennsylvania’s Future, also known as PennFuture, has filed a lawsuit against an Ultra Petroleum subsidiary, alleging that some of the company’s facilities in the Marcellus Shale violate the federal Clean Air Act and state regulations.

Attorneys for PennFuture filed the lawsuit Thursday in U.S. District Court for the Middle District of Pennsylvania.

At issue is the Marshlands Play, a system of facilities operated by Ultra Resources Inc. spread across 558 square miles in Elk and Gaines townships in Tioga County, and Abbott, Pike and West Branch townships in Potter County. According to court documents, Marshlands consists of at least 34 natural gas well pads, seven compressor stations, a network of natural gas pipelines and other equipment.

“Ultra has constructed and operated the Marshlands Play without obtaining all necessary permits and without achieving the lowest achievable emissions rate to control emissions of nitrogen oxides [NOx],” the complaint alleges.

NOx can combine with other elements in the atmosphere to form fine particulate matter and ozone, which are both harmful to people and the environment.

PennFuture says Pennsylvania’s new source review regulations prohibit the construction or operation of a facility with the potential to emit 100 tons per year (TPY) or more of NOx without a permit. The environmental group argues that combined, the facilities in the Marshlands Play emit more than 100 TPY of NOx.

Kelly Whitley, a spokesperson for Houston-based Ultra, told NGI’s Shale Daily the company had not received any information about the lawsuit yet. “They have only issued a news release about it and they haven’t actually served us with the lawsuit,” Whitley said Friday. “We don’t know what the substance of the lawsuit actually is.”

According to court documents, PennFuture is asking the court to order Ultra to comply with the laws, pay civil penalties and the environmental group’s attorney costs and legal fees.