Chemical reaction:

At least 60 chemicals can be used in fracking operations, according to FracFocus, which is managed by two multistate government agencies. The chemical disclosure registry (www.fracfocus.org) contains a list, albeit an incomplete one, of chemicals known to be used in hydraulic fracturing. Here are a few examples:

Hydrochloric Acid: Helps dissolve minerals and initiate cracks in rock

Ammonium Persulfate: Allows a delayed breakdown of the gel

Tetramethyl ammonium chloride: Prevents clay from swelling or shifting

Triethanolamine Zirconate: Maintains fluid viscosity

Polyacrylamide: Slicks the water to minimize friction

Methanol: Winterizing agent

Thioglycolic Acid: Controls iron

Ethylene Glycol: Winterizing agent

Sodium Carbonate: Adjusts pH

Sodium Polycarboxylate: Prevents scale deposits in pipe

2-Butoxyethanol: Product stabilizer

Welcome to Lycoming County, Pa., where energy companies searching for natural gas blast pressurized chemicals through underground shale rock.

In this particular fracking sitesomewhere near the county seat of Williamsportthere’s nothing particularly unique about the chemical stews, composed of 87 percent water and 11 percent sand.

But the other 2 percent is something else, many hard-to-spell ingredients like the biocide tributyl tetradecyl phosphonium chloride and at least one undisclosed trade secret. That’s according to FracFocus, an online chemical disclosure registry where about 200 energy companies have voluntarily opened the cookbook on more than 34,000 U.S. well sites.

The key word is “voluntarily.” When it comes to chemical disclosure, state regulations vary on what must be made public. Members of North Carolina’s seminal Mining and Energy Commission are crafting regulations for drilling, which could launch as soon as 2014. They say disclosure will be one of the first weighty subjects to be considered when they reconvene next month.

The long-term environmental impacts of these fracking fluids are nebulous, critics point out, as are those for fracking in general. Although proponents say it can be done safely, the controversial drilling technique has been criticized for widespread reports of water contamination and increased incidences of earthquakes, even in areas where seismic activity is rare.

Mining and Energy Commission Chairman Jim Womack, a county commissioner in Lee County, where fracking is likely to occur, says he can’t speak for his entire 15-member panel, but he believes North Carolina will enact stringent disclosure laws.

“Our objective is to get as full a disclosure as we can, in consideration of trade secret laws,” Womack says. “That means we’ll probably lean more to the most expansive set of standards that we can find in any other state.”

Just how public that knowledge will be remains to be seen. At the very least, emergency respondersand perhaps environmental regulators such as the N.C. Department of Environment and Natural Resources (DENR)will likely know what frackers are pumping underground, provided they sign a non-disclosure agreement, Womack says.

In a 2012 report to lawmakers, DENR officials recommended that frackers be forced to report their chemical ingredients to environmental regulators, although coveted trade secrets can be kept just thatsecret from the public.

Chemical ingredients, according to FracFocus, are used to ease drilling by reducing friction or killing microorganisms that foul up the machinery, although in most cases, the fluid is primarily composed of water and sand.

Charles Holbrook, a Moore County geologist who worked for three decades with energy companies such as Chevron, chairs the commission’s committee on oil and gas administration.

Holbrook says North Carolina regulations will likely be made up of “best practices” in longtime fracking states. “The challenge here should be to take the Goldilocks rule,” Holbrook says. “Not too hard, not too soft, just right.”

According to Holbrook, some states have allowed companies to keep their secrets for a time, at least for the most part.

“My impression is that no state wants to keep chemical disclosure from emergency responders and medical personnel and so forth,” he says.

However, it’s not just the fracking additives that trouble environmental advocates such as Hope Taylor, executive director of Clean Water for North Carolina. “Groups should also be focusing on the impact of natural materials in drinking water,” she says.

Taylor says naturally occurring, organic substances in shale, some of them flammable or toxic, such as methane and benzene, can move more rapidly into aquifers from fracking operations than water-based frack fluids. In drinking water, they can be as dangerous as the additives.

For Taylor, the more disclosure, the better. “This is our public groundwater,” Taylor says. “The public has a right to know.”

This story has been corrected and clarified. The original story erroneously attributed a statement to Hope Taylor that organic substances in shale include radioactive materials.

This article appeared in print with the headline “The right to know.”