A Greeley ban on oil and gas extraction enacted as a local ordinance in 1985, both by ballot initiative in a home rule city, and by city council action, was overturned by two 1992 Colorado Supreme Court cases, Voss v. Lundvall Bros. Inc and Bowen/Edwards Assoc. Inc. v. Board of County Commissioners of La Plata County, holding that the Colorado Oil and Gas Conservation Act (O&GCA) preempts any outright ban as well as any local regulation that creates an “operational conflict” with O&GCA. Fracking bans and moratoriums in Longmont, Lafayette, Fort Collins and Broomfield have all been challenged in court by the Oil & Gas industry.