HOUSTON — Texas is poised to become the first state to require gas drillers to publicly disclose the chemicals they use to release natural gas from tight rock formations, a groundbreaking measure that could set the stage for other states and the U.S. Congress to move ahead with their own measures to regulate hydraulic fracturing.

But environmentalists caution that the bill — while precedent-setting and a step in the right direction — is still too protective of industry.

“It’s a glass half full kind of thing, pretty good job, pretty good legislation but we didn’t go far enough,” said Cyrus Reed, conservation director of the Sierra Club’s Lone Star chapter.

The bill that passed the Texas House of Representatives today would require mandatory disclosure of many chemicals used in the hydraulic fracturing — or “fracking” — process.