Denver • QEP Resources Inc. will pay $4 million in U.S. fines and install pollution controls to settle a U.S. clean-air case filed by the Department of Justice and the Environmental Protection Agency.

The company has agreed to reduce its emissions at five natural-gas compressor stations on the Uintah and Ouray Reservation in northeastern Utah.

The compressor stations, which remove water and compress natural gas for transportation though gas pipelines, are sources of air pollution, emitting hazardous air pollutants, volatile organic compounds and nitrogen oxides, according to the DOJ.

To fix those problems, QEP has agreed to install additional pollution controls and replace natural gas powered instrument control systems with compressed air control systems, the DOJ said. Those actions will eliminated approximately 210 tons of nitrogen oxides, 219 tons of carbon monoxide, 17 tones of hazardous air pollutants, and more than 166 tons of volatile organic compounds per year.

It also will conserve 3.5 million cubic feet of natural gas each year, which could heat approximately 50 U.S. households.

QEP Resources produces oil and natural gas in the Rocky Mountain states, provides energy companies with field services and operates an underground gas storage site, according to a company's quarterly regulatory filing.

The company was spun off from Utah-based Questar Corp. in 2009.