GRAND JUNCTION – Two Colorado counties joined a statewide lawsuit against new oil and gas air-quality rules they say unfairly impact rural areas.

Garfield and Mesa counties joined seven other counties in the lawsuit against the state Air Quality Control Commission, Air Pollution Control Division and Department of Public Health and Environment, The Daily Sentinel reports.

The lawsuit opposes rules the commission adopted among a suite of regulations state agencies would use to comply with a bill rewriting oversight of oil and gas development.

The other plaintiffs include Moffat, Rio Blanco, Cheyenne, Logan, Phillips, Sedgwick, and Yuma counties.

The counties are members of the Western and Rural Local Government Coalition, which consists of 15 counties and eight municipalities. The coalition members jointly participated in the process that developed the air-quality rules.

The coalition supported most of the regulation revisions the Air Pollution Control Division proposed, “including cost-effective regulations designed to reduce methane and ozone-forming VOCs,” or volatile organic compounds, the lawsuit said.

The counties challenged other new measures including emission controls on certain storage tanks and semi-annual leak detection and repair inspections for facilities with specific emission levels.

The counties “will bear a disproportionate share of the costs of the Commission’s increased regulation,” the lawsuit said.