PA Natural Gas and the Fracking Debate

I was reminded recently of an episode of This American Life about Pennsylvania natural gas, the hydrofracturing debate, and two PA professors’ predictions abut natural gas.  

Here is a description of the episode: 

A professor in Pennsylvania makes a calculation, to discover that his state is sitting atop a massive reserve of natural gas—enough to revolutionize how America gets its energy. But another professor in Pennsylvania does a different calculation and reaches a troubling conclusion: that getting natural gas out of the ground poses a risk to public health. Two men, two calculations, and two very different consequences. (Transcript)