Much of the debate over fracking for natural gas has centered around the potential to pollute drinking water. What's not explicit in much of the discussion is that - in Pennsylvania - the only thing that has polluted people's well water as a result of drilling is natural gas itself.
Known as "methane migration" or "stray gas," the appearance of natural gas in people's well water is behind the image of the flaming tap made famous in the film "Gasland."
The residents of Dimock, in Susquehanna County, featured in that film received settlements from Cabot Oil & Gas, which the Pennsylvania Department of Environmental Protection determined improperly cemented the casings to its wells, thus allowing gas to migrate into the local aquifer and people's wells.
A new peer-reviewed study demonstrates the appearance of gas in a water well - especially in the northeastern part of Pennsylvania around Dimock - is not necessarily the result of drilling.
Natural gas, the study shows, is often already in the water before any drilling...