WASHINGTON ― Fracking-relate d activities “can impact drinking water resources under some circumstances,” according to the final version of an Environmental Protection Agency report released Tuesday.

The report strikes a controversial line from its June 2015 draft version, which said that although there were “specific instances” where the integrity of fracked wells or the handling of wastewater affected drinking water, “hydraulic fracturing activities in the U.S. are carried out in a way that have not led to widespread, systemic impacts on drinking water resources, there are potential vulnerabilities in the water lifecycle that could impact drinking water.”

Fracking uses a high-pressure stream of water, sand and chemicals to tap into shale formations and release oil and natural gas; there have been concerns that fracking or the disposal of wastewater could impact groundwater supplies. Congress had asked the agency to assess those concerns in 2010.

The EPA’s Science Advisory Board, an independent body that reviews agency research programs and provides advice, said in August that it had concerns about the “clarity and adequacy of support” for several of the draft report’s major findings. The board said it was concerned that the findings presented in the report’s executive summary were “ambiguous and appear inconsistent with the observations, data, and levels of uncertainty presented and discussed” in the full report.

The EPA said the line about there being no “widespread, systemic impacts” wasn’t included in the final version of the report because “data gaps and uncertainties” have limited the agency’s ability to “fully assess the potential impacts on drinking water resources both locally and nationally.” The report should not be interpreted as a comprehensive list of incidents because of these gaps, the agency said.

“The report provides valuable information about potential vulnerabilities to drinking water resources, but was not designed to be a list of documented impacts,” the EPA said in a release.

The changes reflect the comprehensive review process that the report has undergone since its first draft, Dr. Thomas A. Burke, deputy assistant administrator of the EPA’s Office of Research and Development, told reporters on Tuesday.

“The sentence did not clearly communicate the findings of the report,” he said. “Scientists put that language in the draft report, and science decided not to put it in the final report.”

Burke said the final report includes a lot of important and useful information for states and localities that want to understand how hydraulic fracturing could affect the water cycle, and what could be done to ensure its integrity.

“This is an unprecedented study in terms of national breadth, detailed focus and stakeholder involvement,” Burke said.

The draft report became a Rorschach test for how people felt about fracking. The oil industry read it as proof that there was no evidence of widespread contamination, while environmental advocates highlighted that there had, in fact, been specific incidents. Environmental groups said the final version makes what they said last year more clear.

“EPA’s initial draft misled the public about the pollution risks of unconventional oil and gas development,” Mark Brownstein, the vice president for climate and energy at the Environmental Defense Fund, said in a statement. “The revised assessment puts an end to the false narrative of risk-free fracking that has been widely promoted by industry. It opens the door for policy improvements and scientific advancements that could better protect the people and places most impacted.”