An influential science journal has issued a correction to a paper on fracking and water safety, after revelations that the authors did not disclose their financial ties to energy giant Chesapeake Energy. The correction was prompted by an article in InsideClimate News in April.

The paper, published in the journal Environmental Science & Technology, concluded that drinking water wells near natural gas sites are not at greater risk of methane contamination than those farther way. It was based on more than 11,000 water samples from Pennsylvania fracking country. Citing its breadth, the authors said the paper challenges smaller studies that link gas drilling to methane pollution.

Chesapeake, the nation's second-largest producer of gas, provided the samples to the research team, led by Donald Siegel, chairman of earth sciences at Syracuse University.

While that was disclosed in the paper, Siegel failed to divulge that he had been compensated by Chesapeake for his work. The authors also did not disclose that one of the co-authors, Bert Smith, worked for Chesapeake during part of the period when the study took place.

In an unusually long, first-page correction, the American Chemical Society, which publishes ES&T, said that Siegel was "funded privately by Chesapeake for his work." It also confirmed that Smith worked for Chesapeake from May 2012 to September 2013, part of the study period. Smith now works for a contractor for Chesapeake.

"The opinions and conclusions expressed in this paper are strictly those of the authors and do not necessarily reflect those of Chesapeake Energy," the authors wrote in the correction.

The full correction, click to read:

Prompted by an ICN story, the journal ES&T issued a correction to a fracking study for failing to disclose industry ties. The correction is now the paper's first page.

Glenn Ruskin, spokesman for the ACS, said "transparency is absolutely essential" when it comes to high-stakes research on the risks that gas drilling may pose to drinking water.

ACS has not yet changed its disclosure policies in response to the problems with the Siegel study. The various ACS journals publish more than 40,000 research articles annually, and they lack the staff to check the backgrounds of all authors for conflicts of interest. As a result, the ACS journals, like most scientific journals, rely on an honor system for authors.

Still, Ruskin said the Siegel study could prompt ACS's publications group to look at new ways to ensure authors divulge all potential conflicts. Further, the questions that emerged about the authors' ties to Chesapeake could heighten other editors' scrutiny of their work.

"Clearly, one of the outcomes of this is their own credibility in their particular community," Ruskin said of the study's researchers. "It does raise a flag with an editor of a journal when an author comes in with these kinds of issues in the past."

Gretchen Goldman, lead analyst at the Union of Concerned Scientists' Center for Science and Democracy, commended the journal for issuing the clarification.

"I'd say that's really notable that they went to that extent of disclosure. I'm glad the journal really recognized the importance of this," she said.

Stakes Are High

Whether the process of hydraulic fracturing, or fracking, can pollute drinking water is a hotly contested issue, with implications for future U.S. regulation of the fossil fuel sector and ensuring water safety for many Americans.

Earlier this week, a study in the Proceedings of the National Academy of Sciences found the presence of chemicals used in fracking fluids in the drinking water of three Pennsylvania households. State regulators had previously detected methane in their water. Industry has long asserted that fracking fluid has never migrated to or tainted drinking water aquifers.

Siegel has said his study refutes the earlier and widely cited work of former Duke University earth science professor Robert Jackson. Known as the "Duke studies," the papers have found a correlation between proximity to gas development and elevated concentrations of methane in residential well water.

Methane, the main component of natural gas, is not toxic for humans. But if the gas escapes from water taps and accumulates in confined spaces such as basements it poses a risk of explosion.

Siegel's findings have bolstered the position of the fossil fuel industry and its backers, who say that fracking is safe and poses no threat to water supplies. The study helped earn him a panel seat at an April 23 hearing on fracking convened by the House Science Committee, led by Republican Lamar Smith of Texas, a champion of oil and gas development.

When asked by Virginia Democrat Don Beyer about the lack of disclosure of his ties to Chesapeake, Siegel played down the concerns and said other scientists could infer that the company had compensated him.

"The editors and everyone else at the journal fully understood by the bylines under our names that it would be obvious that we were being paid by Chesapeake," Siegel said. "Chesapeake, or any of these large corporations, is not just going to hand over...analyses and say just do with them what you want. It was a collaborative agreement. So my colleagues across the country, when they start seeing these blogs about me, say that I...must have been paid by Chesapeake. But I guess it is an oversight [not to disclose, because] people brought it up."

Ruskin of ACS refuted Siegel's assertion about the obvious nature of the authors' ties to Chesapeake.

"It's difficult, if not impossible, for us to be able to divine that without full disclosure," he said.