FILE - In this Tuesday, Feb. 24, 2015 file photo, an activist waves a placard calling for the ban of fracking during a news conference outside the Colorado Convention Center in Denver as the Oil and Gas Task Force meets inside the facility to put the final touches on recommendations for Colorado Gov. John Hickenlooper to consider in the settlement of disputes over oil and gas drilling. The Colorado Supreme Court agreed on Monday, Sept. 21, 2015, to decide whether cities can ban hydraulic fracturing, stepping into a high-stakes battle to determine if local governments can impose tougher oil and gas rules than the state. (AP Photo/David Zalubowski, file)