The U.S. Environmental Protection Agency (EPA) has released its widely anticipated final report on hydraulic fracturing, or fracking, confirming that the controversial drilling process indeed impacts drinking water "under some circumstances." Notably, the report also removes the EPA's misleading line that fracking has not led to "widespread, systemic impacts on drinking water resources."

"The report, done at the request of Congress, provides scientific evidence that hydraulic fracturing activities can impact drinking water resources in the United States under some circumstances," the agency stated in a media advisory.

This conclusion is a major reversal from the EPA's June 2015 pro-fracking draft report. That specific "widespread, systemic" line baffled many experts, scientists and landowners who—despite the egregious headlines—saw clear evidence of fracking-related contamination in water samples. Conversely, the EPA's top line encouraged Big Oil and Gas to push for more drilling around the globe.

But as it turns out, a damning exposé from Marketplace and APM Reports revealed last month that top EPA officials made critical, last-minute alterations to the agency's draft report and corresponding press materials to soft-pedal clear evidence of fracking's ill effects on the environment and public health.

Thomas Burke, EPA deputy assistant administrator and science advisor, discussed the agency's final report released Tuesday.

“There are instances when hyrdofracking has impacted drinking water resources. That's an important conclusion, an important consideration for moving forward," Burke told reporters today, according to The Hill.

Regarding the EPA's contentious "national, systemic conclusion," Burke said, "that's a different question that this study does not have adequate evidence to really make a conclusive, quantified statement."

In the new report, the authors heeded to the EPA's independent Science Advisory Board's advice to review the "widespread systemic impacts" line from the June 2015 draft study. The final 1,200-page report omits that line.

"Scientists put that language in the draft report, and scientists made the decision not to include it in the final report based on feedback from the Science Advisory Board and their interpretation of the available science," Burke explained.

The Science Advisory Board also took issue with how the draft report inexplicably omitted three critical fracking-contamination cases—Dimock, Pennsylvania; Parker County, Texas; and Pavillion, Wyoming.

As Pavillion rancher and affected landowner John Fenton testified last year, "When EPA launched its national study of fracking's drinking water impacts, we thought they'd look first here in Pavillion where they'd already found pollution. But instead they ignored us without explanation. Science means taking the facts as they are. But EPA seems to be intent on finding the facts to support the conclusion they've already reached—'fracking is safe.'"

These specific cases studies are now mentioned in the final report.

In the new report, the EPA has identified cases of impacts on drinking water at each stage in the hydraulic fracturing water cycle:

• Water withdrawals for hydraulic fracturing in times or areas of low water availability, particularly in areas with limited or declining groundwater resources;

• Spills during the management of hydraulic fracturing fluids and chemicals or produced water that result in large volumes or high concentrations of chemicals reaching groundwater resources;

• Injection of hydraulic fracturing fluids into wells with inadequate mechanical integrity, allowing gases or liquids to move to groundwater resources;

• Injection of hydraulic fracturing fluids directly into groundwater resources;

• Discharge of inadequately treated hydraulic fracturing wastewater to surface water resources; and

• Disposal or storage of hydraulic fracturing wastewater in unlined pits, resulting in contamination of groundwater resources.

Burke said that the EPA's assessment "provides the scientific foundation for local decision makers, industry, and communities that are looking to protect public health and drinking water resources and make more informed decisions about hydraulic fracturing activities."

"This assessment is the most complete compilation to date of national scientific data on the relationship of drinking water resources and hydraulic fracturing," he added.

Unsurprisingly, the oil and gas industry has criticized the report.

“It is beyond absurd for the administration to reverse course on its way out the door," American Petroleum Institute Upstream Director Erik Milito told The Hill. "The science and data clearly demonstrate that hydraulic fracturing does not lead to widespread, systemic impacts to drinking water resources. Unfortunately, consumers have witnessed five years and millions of dollars expended only to see conclusion based in science changed to a conclusion based in political ambiguity."

The industry-funded group Energy In Depth added that despite change in the central conclusion, the report still “blows apart the anti-fracking campaign's most common claim, namely that hydraulic fracturing is polluting groundwater all across America."

Meanwhile, public health and environmental groups and activists are saying the opposite.

"At last the EPA confirms what independent science has overwhelmingly determined for years, that drilling and fracking contaminate drinking water," said actor and prominent environmentalist Mark Ruffalo on behalf of the national Americans Against Fracking coalition.

"Across the country, Americans have had their lives turned upside down as fracking has poisoned the water coming out of their faucets and has made their families sick. Now all of our federal and state elected officials need to take action to protect Americans by banning fracking. Water is life," Ruffalo said.

Greenpeace researcher Jesse Coleman agreed. "The EPA's final report on impacts of fracking on groundwater has concluded what too many Americans already know from personal experience: Fracking has caused lasting harm to drinking water sources throughout the country," Coleman said. "The most important findings from this study is that drilling, fracking, and the use of hazardous chemicals necessary to frack have caused groundwater contamination. This puts to rest the widely repeated lie that fracking is 'safe' and has never caused drinking water contamination."

Julia Walsh from Frack Action said, "The EPA has rightly reported that fracking causes water contamination. For all of the Americans living with this tragedy every day, they are finally validated by the federal government."

Similarly, David Braun, Rootskeeper director, said "Kudos to President Obama's EPA for embracing the science about fracking, which clearly demonstrates serious and inherent problems with the practice."

"The EPA could have bowed to pressure from the oil and gas industry and didn't, however, now that the EPA has acknowledged the serious inherent problems with fracking, it is incumbent upon the Obama Administration to stand with the thousands of Americans who have had their water poisoned, and protect them from this dangerous practice," Braun continued.

Earthworks policy director Lauren Pagel said that President-elect Donald Trump and his pro-fossil fuels cabinet should take the EPA report to heart.

"By listening to its scientists instead of its political advisors, EPA's fracking study sets an example that we hope, but do not expect, the Trump Administration to follow," Pagel said. "But a Scott Pruitt EPA would have to ignore 5 years of scientific study, and years of community impacts, to do otherwise. Unfortunately for the still suffering citizens of Pavillion, WY, Dimock, PA and Weatherford, TX, their EPA investigations didn't have advisory boards to publicly remind EPA that science trumps politics."

And Wenonah Hauter, the executive director of Food & Water Watch, said that "the EPA has confirmed what we've known all along: fracking can and does contaminate drinking water. We are pleased that the agency has acted on the recommendations of its Science Advisory Board and chosen be frank about the inherent harms and hazards of fracking."