Texas could soon become the first state to require drilling companies to publicly disclose the chemicals they use to crack tight rock formations in their search for natural gas.

Legislation approved Sunday night in the Texas House could prompt the U.S. Environmental Protection Agency and other states to make similar rules. The governor hasn't indicated whether he'll sign it.

At issue is hydraulic fracturing, or "fracking." The contentious technique allows oil and gas companies to permeate tight shale formations and release once out-of-reach minerals. Drillers pump millions of gallons of chemically laced water into the ground to break the rock, allowing natural gas to flow.

Many companies refuse to say what chemicals are used, arguing it could harm their competitive edge. Others fear the chemicals could taint groundwater or soil.