Consumer Federation of California

State lawmakers will hold a hearing next month to examine the regulation of hydraulic fracturing, or "fracking," in California.

Unlike other major oil-producing states, California does not require energy firms to disclose where they use the controversial procedure or what chemicals they inject into the ground. Regulators released draft rules for fracking last month that would mandate such disclosure but allow oil companies to keep secret the names of certain chemicals they claim to be proprietary.

Lawmakers have expressed concerns about that provision, raising safety questions about the hundreds of chemicals used ‘ many of them known carcinogens ‘ and the potential for drinking water contamination.

The joint hearing of the Senate Natural Resources and Water and Environmental Quality committees is set for Feb. 12.

Legislation to regulate fracking died last year in the face of industry opposition. Oil companies say the technology is safe and that the trade-secrets clause is necessary to protect their competitive advantage.

At least two lawmakers — state Sen. Fran Pavley (D-Agoura Hills) and Assemblyman Bob Wieckowski (D-Fremont) — have revived legislation to compel disclosure, even as regulators undertake the rulemaking process.