“It’s not fracking itself, but the sloppy practices surrounding it—or pre-existing issues that hadn’t been studied before fracking started—that cause groundwater contamination, a study released in Vancouver has found.

In other words, fracking is only as good, or harmful, as the companies that practice it. And groundwater needs to be studied in places where fracking is planned, as well as regulated closely.

Those are the conclusions and recommendations of a study, which was funded by the Energy Institute at the University of Texas at Austin and released at the annual meeting of the American Association for the Advancement of Science (AAAS), which runs from February 16 through 20.

The lack of scientific evidence proving cause and effect between incidents like flammable tap water, a dramatic scene in the award-winning 2010 Josh Fox documentary Gasland, and fracking led the Energy Institute team on a quest to “separate fact from fiction,” as they said on the university’s website, and verify the science behind the contamination allegations. In hydraulic fracturing, or fracking, holes are drilled deep into shale beds and are then injected with a highly pressurized mixture of water, sand and chemicals to liberate trapped natural from pockets of rock. The water and chemicals must be cleaned up after the gas is liberated, and here is where fracking allegedly falls short.

“Given the magnitude of the resources that are becoming available in both countries—the United States and Canada—this is a major issue,” said Energy Institute director Raymond Orbach in a video ahead of the conference.

The researchers, led by the Energy Institute’s associate director, Charles “Chip” Groat, said they did not find evidence that chemicals used in hydraulic fracturing (the clinical name for fracking) were present in and thus contaminating aquifers.

“The bottom line conclusion of our study is that in the states we investigated, we found no evidence that hydraulic fracturing itself, the practice of fracturing the rocks, had contaminated shallow groundwater,” he said at the AAAS meeting, according to BBC News. The study was conducted in the Barnett Shale, in north Texas; the Marcellus Shale, in Pennsylvania, New York and portions of Appalachia; and the Haynesville Shale, in western Louisiana and northeast Texas, the Energy Institute said.”