Originally aired on 7/8/2011

Host Ira Glass tells the stories of two professors, each making a calculation that no one had made before. One gets acclaim. One ends up out of a job. The first, Terry Engelder, a geologist at Penn State, was estimating the amount of natural gas that's recoverable from the Marcellus shale, a giant rock formation that's under Pennsylvania and several other Eastern states. The second, Conrad "Dan" Volz, at the University of Pittsburgh, estimated how much toxic crap—chemicals and pollution from gas exploration—might be getting into water supplies.

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