Environmentalists are suing the Wyoming Oil and Gas Conservation Commission, saying the state agency is honoring companies' requests to keep the ingredients in hydraulic fracturing fluids proprietary despite insufficient justification.
The groups Powder River Basin Resource Council, Wyoming Outdoor Council, Earthworks and OMB Watch sued in Natrona County District Court on Monday.
Hydraulic fracturing involves pumping water, sand and chemicals into oil and gas wells to crack open fissures. Wyoming has required oilfield service companies to tell the state the ingredients in their fracking fluids since 2010.
Wyoming's open records law provides an exception for public disclosure of trade secrets. The groups say the commission has allowed companies to invoke that on flimsy grounds.
State Oil and Gas Supervisor Tom Doll is following its regulation and the open records law.