2 researchers from Duke University studied contamination of water supplies in Pa from gas industry activities. Their work was published in the Proceedings of the National Academy of Sciences. They did not find that fracking fluids had gotten into drinking water, but did find methane and similar contaminates. Apparently, the gas industry activities can release naturally occurring methane, which can then get into well water. PA. Sec. of DEP Krancer (a former coal industry executive) attacked the Duke University's research before a congressional committee.
Here are excerpts of their response, as printed in the Philadelphia Inquirer a few days ago.
http://articles.philly.com/2011-12-02/news/30467569_1_drinking-water-water-resources-methane"Our paper went through rigorous peer review before publication. In his testimony, Krancer praised the conclusions of the independent, nonpartisan U.S. Shale Gas Production Subcommittee, which the Department of Energy established to improve the safety of hydraulic fracturing. That group called our research "credible."
The secretary also said we "inexplicably declined DEP's reasonable request" to share our data and water sampling locations, which "raises credibility questions." That's simply not true.
Krancer made similar accusations when our paper came out. When we first heard them from a reporter, we were so surprised that we suggested he call his source back and make sure it wasn't a mistake. The next morning, we started calling the secretary to clear things up and see if he would be willing to collaborate. Six months and half a dozen phone calls and e-mails later, we're still waiting for a response.
...Today, we're re-extending the offer we made in May and put in writing in June: a partnership with the DEP in which both parties share all their data. The goal would be to understand where any pollution occurs and why, and to make shale-gas extraction as safe as possible. Will the secretary join us?"