Fracking supporters were boosted Thursday by a new Environmental Protection Agency report finding the controversial oil-and-gas extraction process has not caused "widespread" harm to drinking water. 

The findings were contained in a draft assessment, as part of a report requested by Congress. 

The report said the agency "did not find evidence" that any process has "led to widespread, systemic impacts on drinking water resources in the United States." 

The agency did say the controversial drilling technique could affect drinking water if safeguards aren't maintained. It found specific instances where poorly constructed drilling wells and improper wastewater management affected drinking water resources. 

But the EPA also reported the number of cases was small compared with the large number of wells that use hydraulic fracturing, better known as fracking. 

For industry and congressional voices who have long argued the health hazards associated with fracking are overblown, the report appeared to be a boon. 

"Today's study confirms what we already know. Hydraulic fracturing, when done to industry standards, does not impact drinking water," Sen. Lisa Murkowski, R-Alaska, chairwoman of the Senate Energy and Natural Resources Committee, said in a statement. "States have been effectively regulating hydraulic fracturing for more than 40 years and this study is evidence of that." 

In New York state, the EPA report already was fueling calls to rescind the state's fracking ban. 

"I fully expect Governor Cuomo to reverse his previous decision to ban fracking which was based upon controversial scientific studies and made to appease far left environmentalists," Rep. Chris Collins, R-N.Y., said in a statement. "Hardworking New Yorkers deserve the job opportunities and economic growth fracking has clearly produced in other states, including neighboring Pennsylvania." 

The Business Council of New York State also put out a statement Thursday urging the ban's reversal. Other states, meanwhile, have gone in the opposite direction from New York. Texas recently approved a bill barring local ordinances against fracking. 

Improved drilling techniques have led to a surge in fracking in recent years that has fueled a nationwide boom in production of oil and natural gas, as fracking wells sprout up from California to Pennsylvania. Fracking involves pumping huge volumes of water, sand and chemicals underground to split open rocks to allow oil and gas to flow. 

Improved technology has allowed energy companies to gain access to vast stores of oil and natural gas underneath states from coast to coast but has raised widespread concerns that it might lead to groundwater contamination and even earthquakes. 

The EPA assessment tracked water used throughout the fracking process, from acquiring the water to mixing chemicals at the well site and injecting so-called "fracking fluids" into wells, to collection of wastewater, wastewater treatment and disposal. 

The report identified several vulnerabilities to drinking water resources, including fracking's effect on drought-stricken areas; inadequately cased or cemented wells resulting in below-ground migration of gases and liquids; inadequately treated wastewater discharged into drinking water resources; and spills of hydraulic fluids and wastewater. 

Environmental groups seized on the report's identification of cases where fracking-related activities polluted drinking water. Lauren Pagel, policy director of the environmental group Earthworks, said, "Today EPA confirmed what communities living with fracking have known for years: fracking pollutes drinking water." 

"Now the Obama administration, Congress and state governments must act on that information to protect our drinking water and stop perpetuating the oil and gas industry's myth that fracking is safe," she said. 

But with the EPA finding no widespread impact, industry groups hailed the EPA study as proof that fracking is safe. 

"After more than five years and millions of dollars, the evidence gathered by EPA confirms what the agency has already acknowledged and what the oil and gas industry has known: hydraulic fracturing is being done safely under the strong environmental stewardship of state regulators and industry-best practices," said Erik Milito, upstream group director of the American Petroleum Institute, the oil industry's top lobbying group. 

Sen. James Inhofe, R-Okla., chairman of the Senate Environment and Public Works Committee, said the report marked "the latest in a series of failed attempts" by the Obama administration to link fracking to systemic drinking water contamination. 

"The Obama administration is now zero for four," Inhofe said. "EPA, the U.S. Geological Survey and others have said that hydraulic fracturing is indeed safe." 

EPA officials said the report was not intended to prove whether fracking is safe, but instead was aimed at how state regulators, tribes, local communities and industry can best protect drinking water and reduce the risks of fracking. 

"It's not a question of safe or unsafe," Tom Burke, deputy assistant administrator of EPA's Office of Research and Development, said in a. conference call with reporters. The issue for the EPA is "how do we best reduce vulnerabilities so we can best protect our water and water resources?" Burke said. 

The Associated Press contributed to this report.