The US government unveiled plans Thursday to set national standards for wastewater discharges from natural gas drilling amid growing concern over water pollution from a technique known as "fracking."

The Environmental Protection Agency said it would accept comments for new standards over the coming months for shale gas extraction as well as for gas from underground coalbeds.

"No comprehensive set of national standards exists at this time for the disposal of wastewater discharged from natural gas extraction activities," the agency said in a statement.

The new regulations come in the face of criticism that the frenzy for natural gas exploration and new horizontal drilling techniques such as hydraulic fracturing or fracking to extract gas from shale formations would lead to contamination of underground water supplies.

EPA Administrator Lisa Jackson said the administration of President Barack Obama "has made clear that natural gas has a central role to play in our energy economy."

"That is why we are taking steps -- in coordination with our federal partners and informed by the input of industry experts, states and public health organizations -- to make sure the needs of our energy future are met safely and responsibly," she added.

"We can protect the health of American families and communities at the same time we ensure access to all of the important resources that make up our energy economy," she added.

EPA noted that production from shale formations has grown from a negligible amount just a few years ago to almost 15 percent of total US natural gas production and this share is expected to triple in the coming decades.

Industry analysts say that recent discoveries of shale formations in several regions would make the United States the Saudi Arabia of natural gas.

But there are concerns that wastewater associated with shale gas extraction is prohibited from being directly discharged to waterways.

Critics say the industry has moved too fast with little regulation, and cite concerns about spills, leaks and contamination from chemicals used in the process. Similar debates are ongoing in Canada, France and other countries.

The EPA said it would gather comments for rules to implemented by 2014 for shale gas.

But witnesses at a Senate hearing shortly after the announcement pointed out that the rules may affect only a small percentage of fracking operations because many drillers recycle the fluids used from one well to another.

"Virtually all of it is being recycled" in the eastern Marcellus Shale formation, said Tom Beauduy of the Susquehanna River Basin Commission, a regional water authority based in Pennsylvania, where thousands of wells are being drilled.

Cynthia Dougherty of the EPA's Office of of Water told the hearing the new rules would help prevent the overloading of wastewater treatment facilities, which may be poorly equipped to handling fracking discharges.

Katy Dunlap of Trout Unlimited told the Senate Energy and Natural Resources Committee hearing it was unclear how much wastewater was being recycled by the industry. And she said the gas boom has led to other types of pollution from construction of roads, pipelines and other infrastructure that leads to sediment runoff.

In Pennsylvania alone, the state has issued 900 violations for well operators, Dunlap said, while praising the EPA for the new initiative.

"We applaud the EPA announcement today," she said.

Other activists said the EPA is not moving quickly enough to protect against pollution from gas exploration.

"The nation is in the midst of a fracking-fueled gas rush which is generating toxic wastewater faster than treatment plants can handle it," said Deborah Goldberg of the environmental group Earthjustice in a statement.

"The EPA's proposal is a common sense solution for this growing public health problem... These protections should be implemented right away. The millions of Americans who depend on drinking water that comes from the gasfields can't wait much longer."