New rules for hydraulic fracturing and other petroleum industry practices on federal land are headed before a judge in Wyoming.
Four states and two petroleum industry groups are suing the U.S. Interior Department, saying the rules announced in March are unnecessarily burdensome for oil and gas developers.
The rules are set to take effect Wednesday. Colorado, North Dakota, Utah, Wyoming, the Western Energy Alliance and the Independent Petroleum Association of America seek to suspend the rules pending the outcome of their lawsuit.
U.S. District Judge Scott Skavdahl has scheduled arguments for and against that request at a hearing Tuesday in Casper.
States including Wyoming claim they already have effective regulations for oil and gas drilling. The federal government and environmental groups say the rules are necessary to protect federal land.