Wyoming regulators have agreed to keep secret the identities of 146 chemicals used in hydraulic fracturing since disclosure rules went into effect nearly a year ago, according the the state’s oil and gas supervisor.

The Wyoming Oil and Gas Conservation Commission granted the trade secret exemptions to 11 companies, said Tom Doll, commission supervisor.

It’s the first release of the number of exemptions since state rules regarding hydraulic fracturing, or ‘fracking,’ went into effect in September.

Doll, who released the numbers at the Petroleum Association of Wyoming’s annual meeting in Casper on Wednesday, said no company has requested blanket exemptions for all chemicals.

“It’s just been steady requests, a few a month,” he told the Star-Tribune after his presentation.

According to the commission’s website, the companies that received the exemptions were CESI Chemical Inc., Nalco Co., CalFrac Well Services Corp., Multi-Chem Group LLC, Baker Hughes, Halliburton Energy Services Inc., BJ Services Co., Core Lab Reservoir Optimization, SNF Inc., Spectrum Tracer Services, and Water Mark Technologies Inc.

Wyoming’s open records law includes an exemption for trade secrets. Under the state’s regulations, companies may request that the Oil and Gas Conservation Commission classify the identity of a chemical used in fracking as a trade secret.

If state regulators agree, the chemical’s identity is kept secret. If not, regulators release the chemical’s name to the public.

Fracking is used to develop nearly all oil and gas wells in the state.

Wyoming’s fracking fluid disclosure rules, the first of their kind in the nation, have attracted concern from environmental groups and some landowners in the state who are worried about the identity and concentration of chemicals used in the process and fear such chemicals could pollute drinking water.

Some have advocated for complete disclosure of all chemicals used in fracking, in which water, sand and chemicals are pumped underground to fracture formations and allow oil and gas to flow.

Doll, the Oil and Gas Conservation Commission supervisor, said 37 percent of the exempted chemicals are used as tracers in fracking fluid to show the reach of the underground fractures.

Subscribe to Breaking News

* I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.

Such chemicals — at a cost of thousands of dollars — provide a signature that could help prove or disprove claims that fracking harms drinking water supplies, he said.

“If you didn’t care if that frack went up or out, you wouldn’t be spending that kind of money,” he told members of the state’s petroleum association. “So I think that’s a good story.”

Another 50 percent of the chemicals are used in the mix pumped underground to fracture the formations, Doll said.

John Robitaille, a vice president of the Petroleum Association of Wyoming, said he was surprised that so many of the exempted chemicals were used as tracers. He said the number indicates the state has tight qualifications for the exemption that are not easily obtained.

I think the law is very clear on what is and what is not allowed under those types of situations, and I think that’s very helpful,” he said. “So in those instances, it’s very easy for the company to review that law and say, ‘I think I have a case or I definitely do not have a case.’”

Doll recalled that he has rejected exemption requests from two companies to date. Neither resubmitted those requests.

“I think they realized they didn’t meet our criteria,” he said.

Subscribe to Breaking News

* I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.

Reach Jeremy Fugleberg at 307-266-0623 or jeremy.fugleberg@trib.com. Read his blog at trib.com/news/opinion/blogs/boom and follow him on Twitter: @jerenegy.