A coalition of environmentalists filed a petition Monday saying the Wyoming Oil and Gas Conservation Commission granted exclusions allowing natural gas producers to hold secret the constituents in their hydraulic fracturing fluid without justification.

The state's Oil and Gas Supervisor, Tom Doll, maintains the commission is following its Hydraulic Fracturing Disclosure Rule and the Open Records Act.

"If they are granted the trade secret status those records are kept confidential and would not be released unless there was an incident that would require responders to have disclosure of the chemical compounds in use."

Wyoming is the only state to require oilfield service companies to reveal the ingredients in fracking fluids.

The coalition of environmental groups say the commission is allowing companies to invoke exemptions on flimsy grounds.