AUSTIN (CBSDFW.COM) – Texas lawmakers have approved a bill that would be the first law in the nation to require drilling companies to publicly disclose the contents of fluids used in hydraulic fracturing.

Dozens of companies pump fluid into shale formations to break up the rock in order to extract natural gas. Most companies presently keep the chemical composition of the fluid secret.

Under the bill introduced by Republican state Rep. Jim Keffer, companies would have to report the content of the fluid to the Texas Railroad Commission. If the company believes the recipe is a trade secret, they can request that the commission keep the contents confidential. The attorney general would then decide if the claim of a trade secret is legitimate.

The Republican-controlled House approved the measure on a voice vote.

(Copyright 2011 by The Associated Press. All Rights Reserved.)