DURHAM, N.C., May 10 (UPI) -- Groundwater wells in northeastern Pennsylvania and upstate New York are contaminated by methane as a result of "fracking" gas drilling, a university study says.
Researchers at Duke University say 13 of 26 wells tested within a kilometer of sites using the controversial natural gas drilling technique known as "hydrofracking" had elevated methane levels, USA Today reported Tuesday.
Some were contaminated to the point where the water could catch fire, the study said.
The findings, published in the Proceedings of the National Academy of Sciences, found measurable amounts of methane in 51 of a total of 60 wells tested last year, but in those closest to fracking the levels were 17 times higher than average.
The drilling industry was quick to criticize the research.
"What you have here is a paper that draws pretty firm conclusions without much data at all to back any of them up," Chris Tucker, spokesman for Energy In Depth, a Washington coalition of oil and natural gas producers, said in a statement.
"In fact, the authors admit they have no baseline data at all, which makes it impossible to characterize the state of those water wells prior to recent development."
Study co-author Robert Jackson of Duke said researchers have now gathered baseline information for a number of wells and will conduct follow-up tests.