For the first time ever, a study demonstrated that fracking has contaminated underground water reservoirs, BuzzFeed reported. The polluted aquifer is near the small town of Pavillion, Wyoming.

The study’s lead author Dominic DiGiulio, a former EPA scientist, used public records and new water samples to build on an investigation the Environmental Protection Agency stalled in 2013. After receiving complaints from Pavillion residents about the drinking water’s bad taste and smell, the EPA opened an investigation in September 2008, the study reports. The agency sampled domestic wells in March 2009 and January 2010, and issued a preliminary report in 2011. That report showed that chemicals used in fracking had leaked from unlined dumping pits into Pavillion’s groundwater. The drilling industry pushed back against the report, and the EPA never finalized its findings. Instead, in 2013, the agency turned the investigation over to the state of Wyoming, which has issued more inconclusive reports since then.

The EPA "consistently walked away" from fracking investigations

Fracking, shorthand for hydraulic fracturing, uses a high-pressure mixture of water, sand, and chemicals to crack sediment layers that contain oil and natural gas. The technique has alarmed scientists and activists alike for its potential to pollute groundwater and cause earthquakes. But those concerns have not yet been able to trump the fact that fracking has revitalized the US oil and gas industry, according to BuzzFeed.

DiGiulio’s study, released yesterday in the Environmental Science & Technology journal, takes the EPA’s work one step further by showing for the first time that chemicals from fracking wells are polluting a federally protected drinking water reservoir. A report from BuzzFeed, which broke the story, clarifies that DiGiulio's study doesn't actually look at whether contamination has migrated into domestic tap water in Pavillion.

However, a press release from Stanford University, whose scientist Robert Jackson also worked on the study, notes that the Agency for Toxic Substances and Disease Registry warned people in the area to not use tap water for bathing, cooking, or drinking. The study, "suggests there may be widespread impact to underground sources of drinking water as a result of unconventional oil and gas extraction," Di Giulio says.

The press release also notes that the EPA has "consistently walked away" from investigations into human and environmental harm from fracking. The study’s authors urge further investigation and regulations to "avoid what happened in Pavillion."