SACRAMENTO, Calif. (AP) -- Critics of hydraulic fracturing urged lawmakers Monday to impose a moratorium on the controversial drilling technique, saying there is too much uncertainty about its health and environmental effects.
More than two dozen opponents of "fracking" lined up to share their concerns at an Assembly Natural Resources Committee hearing, where lawmakers advanced three bills to prohibit the practice temporarily. The drilling technique involves blasting water, sand and chemicals into deep rock formations to release oil or natural gas.
One measure from Assemblywoman Holly Mitchell, D-Los Angeles, would halt the practice until an advisory panel analyzes the potential consequences.
Mitchell said scientific studies have shown a range of environmental and health effects, both positive and negative. Those mixed conclusions have left her constituents, who live near the Inglewood oil field in Los Angeles County, concerned and confused about whether fracking can be done safely.
"It says to me that we have a cause to pause," Mitchell said.
Representatives for the drilling industry defended the energy extraction efforts, telling lawmakers there have not been any negative environmental effects from fracking during decades of activity in California. About 80 percent of fracking in California occurs in uninhabited areas near Bakersfield, they said.
"For a moratorium to be introduced on something that has been safe for 60 years is something that I truly don't understand," said Paul Deiro, a lobbyist with the Western States Petroleum Association.
Fracking has drawn scrutiny in other states and has just recently become an issue of high interest in California. Oil companies are looking to expand production from the Monterey Shale formation, which stretches from Kern County north through the San Joaquin Valley. It is estimated to be one of the country's largest shale oil formations.
Expanded drilling activity here and in other states has fostered passionate and sometimes heated debate. Opponents at Monday's hearing were scolded several times for applauding a lawmaker's statement in support and laughing at comments from industry officials.
At several points, Assemblywoman Shannon Grove, a Republican representing drilling-heavy Bakersfield, pressed environmental advocates and the author of one bill to show proof of environmental impacts elsewhere and worries about water use.
"You're putting forth legislation that could potentially halt thousands of jobs," Grove said.
Kassie Siegel, of the Center for Biological Diversity, expressed doubts that state regulators, who are in the process of creating California's first fracking rules, are providing enough oversight and that they will craft sufficient safeguards.
She contrasted California's oversight with the moratorium in place in the state of New York, which halted new gas drilling activity pending a health study.
"No public health review is underway," Siegel said. "State oil and gas regulators do not even track fracking, and they are ignoring regulations that should be enforced while instead discussing new rules for fracking that could be years away."
The bills debated Monday are among the more restrictive proposals moving through the Legislature. A measure from Sen. Fran Pavley, D-Agoura Hills, would prohibit state regulators from issuing fracking permits beginning in January 2015 if an independent scientific study has not been completed.
The Assembly bills consideration Monday are carried by Los Angeles-area Democrats. All three passed on identical votes of 5-3, with Republicans in opposition. The measures now go to the Assembly Appropriations Committee.
AB1301 from Assemblyman Richard Bloom, of Santa Monica, would stop fracking until further legislation is enacted outlining how it can occur.
Two similar bills, AB1323 and AB649, call for creating an advisory committee to review health, environmental, economic and other effects. They also would recommend regulatory changes.
Those bills from Mitchell and Assemblyman Adrin Nazarian, of Sherman Oaks, would require state officials to decide by January 2019 if fracking should occur in California.
California was the third-largest oil producing state last year, behind Texas and North Dakota, according to the U.S. Energy Information Administration.
All California oil wells are subject to the same regulations, with no specific rules for those using hydraulic fracturing. The California Department of Conservation released draft fracking regulations in December, and agency officials say they hope to adopt final rules next year.