Natural-gas drilling that may provide a century’s energy for the U.S. must be managed to ensure safe water and air, a top Environmental Protection Agency official said.

“When we know problems exist, EPA will not hesitate to protect Americans whose health may be at risk,” Deputy Administrator Bob Perciasepe said today in testimony before a Senate Environment and Public Works Committee hearing.

The EPA and lawmakers are trying to assess the safety of hydraulic fracturing, or fracking, a technique that injects a mix of water and chemicals into shale to free gas. President Barack Obama is urging the U.S. to tap more gas supplies to become less dependent on foreign fossil fuel. Environmentalists and some federal and state officials say fracking may taint drinking water.

“The U.S. has as much natural gas as Saudi Arabia has oil,” Senator Ben Cardin, a Maryland Democrat, said today. “The natural gas business is booming, but may be in jeopardy.”

New York temporarily banned fracking on concern that the process may contaminate drinking water, while New Jersey is considering a ban and Pittsburgh has prohibited fracking within city limits, according to Cardin. Mountain Lake Park, Maryland, made such drilling illegal, he said.

“The industry has failed to meet minimally acceptable performance levels for protecting human health and the environment,” Cardin said. “That is both an industry failure and a failure of the regulatory process.”

‘It’s Worked’

Senator James Inhofe of Oklahoma, the senior Republican on the committee, said fracking has been conducted safely since it was first employed in the U.S. in 1949.

“The practice has now been used on more than 1 million currently producing wells, 35,000 wells per year, without one confirmed case of groundwater contamination,” Inhofe said. “It’s worked. It’s been successful and we have to keep that for America.”

The EPA is under orders from Congress to study the effects on drinking water of shooting pressurized water and chemicals into rock to free gas. The agency expects to have preliminary results late next year and complete results in 2014, Perciasepe said.

Shale-gas output was 4.87 trillion cubic feet in 2010, the department’s Energy information Administration said in an April 5 release. That’s a 57 percent increase from 3.11 trillion in 2009, according to department data released in December.

“Natural gas can enhance our domestic energy options, reduce our dependence on foreign supplies and serve as a bridge fuel to renewable energy sources,” Perciasepe said.

Using Diesel

Energy companies that use diesel in their hydraulic- fracturing fluids without a permit are in violation of the law, Perciasepe said.

That issue has been a point of contention between the agency and industry since House Democrats issued a report saying 12 companies, including Houston-based Halliburton Co. (HAL), have used diesel fuel in fracking, possibly breaking the law.

Halliburton has said the EPA failed to properly set rules for diesel permits.

“EPA’s continued desire to push the fiction of a historical permitting program for the use of diesel is just counterproductive at this point,” Matthew Armstrong, a lawyer with Bracewell & Giuliani LLP in Washington who represents energy companies, said today in an interview. “EPA needs to drop the threat of enforcement based on some super-secret permitting program.”

Other hydraulic-fracturing fluids aren’t federally regulated.

Pennsylvania Drilling

Senator Bob Casey, a Pennsylvania Democrat, told the committee today that he doesn’t believe concerns about environmental impacts need to curb the pace of natural gas drilling in his state, where 2,650 shale-gas wells have been drilled and land values have soared.

“There’s tremendous growth of this industry and tremendous opportunity with it,” Casey said. “But as we’re doing that, we’ve got to make sure that we get it right.”

The Marcellus Shale, stretching from Tennessee to New York, may hold 490 trillion cubic feet of gas, enough to heat U.S. homes and power electric plants for two decades, according to Terry Engelder, a professor of geosciences at Pennsylvania State University in State College. That would make it the world’s second-largest gas field behind South Pars, shared by Iran and Qatar.

To contact the reporter on this story: Kim Chipman in Washington at kchipman@bloomberg.net

To contact the editor responsible for this story: Larry Liebert at lliebert@bloomberg.net