Environmental groups sue California regulator over fracking

The lawsuit accuses the regulator, the California Department of Conservation, Division of Oil, Gas, and Geothermal Resources, with failing to evaluate the risks, even though fracking was used for 600 wells in the state last year.

Fracking, or pumping chemical-laced water and sand into a well to open cracks that release oil and gas, has generated a fierce debate in the United States, leading to bans in one state and several municipalities. Yet the industry insists the practice is safe so long as wells are properly built.

A non-profit environmental law firm, Earthjustice, filed the lawsuit in Alameda County Superior Court on behalf of the Center for Biological Diversity, Earthworks, Environmental Working Group and the Sierra Club.

"Public outcry has finally forced the Department to take a look at fracking," Earthjustice attorney George Torgun said in a statement. "They've held workshops and say they're considering regulations. But the problem needs attention now before too much damage is done."

In July, the Department of Conservation hosted several workshops to discuss potential regulation in anticipation of increased horizontal drilling in the state, which combined with fracking has unlocked oil and gas reservoirs around the country.

Given the public scrutiny, new rules are not expected to be finalized until mid-2013, officials said. State legislation to halt fracking, however, has so far received little support.

(Reporting by Braden Reddall in San Francisco, editing by Grant McCool)