A hearing is set for federal court in Cheyenne this week over the natural gas industry's attempt to roll back water quality rules for southeastern Montana rivers.

Companies argue the restrictions put a crimp on drilling in Montana and neighboring Wyoming, where tens of thousands of natural gas wells have been installed in the last decade and more are planned.

The gas is extracted from coal seams saturated with salty water. Because that water is pumped to the surface, Montana put a cap on sodium levels in rivers coming out of Wyoming to protect the crops of downstream farmers.

The case pits Marathon Oil and Devon Energy against Montana and the Environmental Protection Agency, which approved the state's water rules.

Thursday's hearing is before U.S. District Judge Clarence Brimmer.