SACRAMENTO, Calif. (AP) — A proposal setting new rules in California for an oil and gas drilling technique known as fracking gained key legislative approval Wednesday.

The measure includes a requirement that drillers disclose the chemicals to use in the process of hydraulic fracturing, which involves injecting water, sand and chemicals into deep rock formations to release oil or natural gas.

Assembly lawmakers passed the plan Wednesday, 47-17. The legislation is expected to get a final vote Thursday in the state Senate, where the bill originated.

Environmentalists across the nation have raised concerns about the whether the chemicals used in the process could harm public health or air and water quality. Industry officials say fracking has been practiced for decades, proving the technique to be safe.

Drilling companies are exploring whether fracking could help them access oil in California's Monterey Shale.

Under SB4, from Sen. Fran Pavley, D-Agoura Hills, state officials would have to complete a study evaluating risks from fracking and other well-stimulation techniques by January 2015. The bill also would require drillers to seek permits and notify nearby landowners before starting work.

The legislation also calls for a state website to publicly list the chemicals used. Nearby landowners would have a chance to have their wells tested before and after fracking begins.

The Assembly approved the bill amid concerns from environmental groups over last-minute changes that they say would exempt fracking from the California Environmental Quality Act, a landmark environmental law.

"Without this bill fracking will continue to go on without oversight," said Assemblyman Adam Gray, D-Merced, during debate. "It's a good bill. It's good for Californians."

Assemblywoman Shannon Grove, R-Bakersfield, said the legislature should wait for pending regulations from the California Department of Conservation's Division of Oil, Gas, and Geothermal Resources.

"It's like you want the Sierra Club to approve anything that goes forward. We need jobs for growth in this state," she said.

Though the department aims to approve its regulations next year, environmental advocates and some Democratic lawmakers say state regulators have done too little to keep up with the industry.

SB4 was the only bill to pass the Assembly this year that regulates fracking. A half-dozen measures proposing fracking rules died in that chamber earlier this year.

Pavley's measure also would regulate other well-stimulation techniques, such as using acid to break up shale rock.