* EPA eyes new regulations for wastewater discharges
* EPA investigating use of diesel in fracking
* Republicans worried about overregulation
* EPA says greenhouse gas fracking leaks can be fixed (Adds details on study on greenhouse gases from fracking)
By Roberta Rampton
WASHINGTON, April 12 (Reuters) - The U.S. Environmental Protection Agency is looking at how best to address wastewater discharges produced by natural gas "fracking," and may revise regulations on wastewater from coal bed methane extraction, a top official said on Tuesday.
Hydraulic fracturing, or "fracking" -- an extraction method that involves blasting water, chemicals and sand into shale rock to release trapped gas -- has raised concerns about its impact on the environment.
Additional federal scrutiny comes as the Obama administration looks for ways to reduce imports of foreign oil and boost natural gas development.
"We believe that this important resource can be -- and must be -- extracted responsibly," Bob Perciasepe, deputy EPA administrator, told a U.S. Senate Environment and Public Works Committee hearing.
Natural gas extraction -- including "fracking" from shale deposits -- can contaminate water supplies unless it is properly managed, Perciasepe said.
Fracking has also been criticized by scientists at Cornell University, who say leaks of methane, a powerful greenhouse gas, at drilling sites can make natural gas an even worse emitter of gases blamed for warming the planet than coal. [ID:nN12172699]
Perciasepe said if there were leaks, they could be plugged. "If indeed there is leakage out of the system, they are generally problems that can be addressed with proper controls or collection controls at the wellhead," he said.
TAKE A LOOK-Future of shale gas [ID:nN18229665]
EPA study plan: link.reuters.com/wyq87r
FACTBOX-Risks to shale gas production [ID:nN28199000]
OVERREGULATION A WORRY-SESSIONS
A 2005 energy law exempted fracking from regulation under the Safe Drinking Water Act, except when diesel is used.
Democratic senators at the hearing pressed Perciasepe on why the EPA is not doing more to crack down on the reported use of diesel for fracking, which can only be done under permit.
"The industry has failed to meet minimally acceptable performance levels for protecting human health and the environment," said Democratic Senator Ben Cardin of Maryland.
Senator Bob Casey of Pennsylvania, where drilling has rapidly expanded in recent years, hopes to push ahead with a law he has proposed that would give the EPA broader authority over fracking.
"We're trying to close the loophole that's in the law as it stands now," Casey said.
But Republicans said states should be allowed to continue to regulate the process, and warned against costly regulations that could stifle the booming sector and the jobs it creates.
"We've got to watch that the regulations and the lawsuits don't become death by a thousand cuts," said Republican Senator Jeff Sessions of Alabama.
EPA INVESTIGATING DIESEL USE
Earlier this year, a Congressional probe found a dozen energy companies used diesel in their fracking operations without permits. For details, see [ID:nN31240520]
The investigation by the U.S. House of Representatives' Energy and Commerce Committee found companies such as Halliburton Co (HAL.N) and BJ Services, which was bought by Baker Hughes Inc BHI.N, injected millions of gallons of fluids containing the fuel into wells between 2005 and 2009.
The EPA is now investigating where diesel was used and whether companies had permits, Perciasepe told senators.
"We are looking into this issue of diesel use and we'll be following up on it soon," he said.
The EPA is hoping for initial results from a peer-reviewed research study on fracking in late 2012, Perciasepe said, noting the agency has obtained information from nine companies on the chemicals and fluids used to extract natural gas.
"If improperly managed, natural gas extraction and production, including hydraulic fracturing ... may potentially result in public health and environmental impacts at any time in the life cycle of a well and its associated operations," Perciasepe said.
(Additional reporting by Timothy Gardner)
(Editing by John Picinich, Jim Marshall and Jeffrey Benkoe)