Rob Jackson studied the water at hundreds of homes near Marcellus fracking wells.
"We asked a simple question: 'Is your water any different if you're living near a natural gas well?'" Jackson said. "And it was a glass half-empty, glass half-full kind of story. We did not find evidence for the chemicals in fracturing fluids, for instance. What we did find was much higher likelihood that you would have gas in your water - methane, ethane or propane, the things that are in the natural gas itself. We think the simplest explanation for that is poor well integrity."
In other words, those mile-long pipes can leak.
"Depending on where you are, five, ten, 20 percent of oil wells have problems with their well integrity through time," said Jackson.
"We're not saying it's a problem every time. But there are a number of cases where there have been problems," said Cornell professor Bob Oswald.
And it's not just people drinking that water. Veterinarian Michelle Bamberger and her husband, Oswald, studied 24 cases where animals had problems.
"Changes in breeding - abortions, still births were more common after drilling than before drilling," said Bamberger.
George Stark's company has racked up a number of violations, for allowing natural gas to pollute the local water.
Pogue asked Stark about the 2010 letter from the Pennsylvania Department of Environmental Protection: "What was that about?"
"That was at a time in 2010 that there was a question of what we would refer to as methane migration," Stark replied. "What we discovered is 70 percent of the water wells in Susquehanna County have preexisting methane in them already."
Today, Pennsylvania gas companies are required to test homeowners' water before and after fracking.
"Prior to that 2010 letter you mentioned, their water well was not tested for methane," Stark said.
"Live and learn," he laughed. "Now we test it everywhere."
Then there's the disposal problem. What do we do with all the poisonous water that comes back up from the fracked well?
"There are still some states where you can spray that water on lands, or where it's used for dust control," said Jackson. "It's a terrible idea. Most of it around the country goes to what are called deep injection wells,' where you take waste water and pump it back underground very deep."
That's half a trillion gallons a year.