Steve Craig is used to oil companies operating near his ranch in the smooth, rounded hills of southern Monterey County.

But Craig draws the line at "fracking."

A company called Venoco Inc. wants to try hydraulic fracturing in the Hames Valley near Bradley, using a high-pressure blend of water, sand and chemicals to crack rocks deep underground and release oil locked in the stone.

The same technique has revolutionized America's natural gas business in the past five years, boosting production and driving down prices. It has also been blamed for tainting groundwater near fracked wells, a charge that drilling companies deny.

Anyone living near the Hames Valley has long experience with the oil industry. The San Ardo oil field - a thicket of pipes, power lines and pump jacks - sits about 5 miles up Highway 101, a source of petroleum and jobs since 1947.

But the possibility of polluted water alarms Craig and others, who have appealed to the county government to block Venoco. The fact that California, so far, does not regulate fracking bothers Craig just as much.

"The agencies have not asked, 'Who's drilling? Which compounds are being used?' " said Craig, who directs a land-preservation group in Monterey County. " 'Where does it go? Does it move up through a fault in the next big earthquake?' No one's asking these questions."

The fight over fracking has finally come to California.

Debates over banning or restricting the practice have raged in New York, Pennsylvania and other states. The U.S. government is studying its safety, while the oil and gas industry maintains that fracking poses no threat to the environment or public health.

Until recently, California remained out of the fray because environmentalists and politicians believed fracking wasn't happening here.

But it is.

Venoco fracked two wells in Santa Barbara County earlier this year, much to the surprise of local officials. The company received permits from Monterey County to drill up to nine wells in the Hames Valley, but Craig and other activists appealed the permits. Farther north, the company plans to frack 20 wells in the Sacramento Basin this year, according to one of its financial reports.

Fracking not tracked in state

Occidental Petroleum Corp., located in Los Angeles, fracked wells in Kern and Ventura counties this spring. The U.S. Bureau of Land Management plans to sell oil-development leases next month in Monterey County, atop a geologic formation that may require fracking to produce much oil or gas.

The small number of individual projects that have come to light in California suggests that the practice is nowhere near as widespread here as it is in states such as Pennsylvania and Texas, where fracking has been used on hundreds of new wells. But no one knows for certain because no one has kept track.

The California agency that regulates the oil and gas industry does not record the number and location of fracked wells, a fact that has astonished and angered some politicians and environmentalists. Nor does the agency - the Division of Oil, Gas & Geothermal Resources - require companies to disclose the chemicals they use in the process.

That may change. In June, the Assembly passed legislation sponsored by Assemblyman Bob Wieckowski, D-Fremont, that would force companies to report the location of each new fracked well as well as the chemicals used. The state, he said, must do a better job monitoring a practice that may become common here.

"This is a baby step," Wieckowski said. "Most of the time we're reactive in government. We wait until the hurricane hits, and then we say, 'Maybe we shouldn't have built homes there.' "

Hydraulic fracturing involves pumping underground large quantities of pressurized water and sand, along with a mixture of chemicals. (The chemicals, which can include household substances such as citric acid and carcinogens such as benzene, typically make up 1 percent of all the material pumped into the well.) The intense pressure breaks the rock, creating a lattice of tiny cracks that the sand props open. Natural gas or oil trapped in the stone flow through the fissures toward the well.