In Pennsylvania, there's an industrial revolution going on. Battalions of drilling rigs are boring into the earth to extract natural gas from an underground layer of shale called the Marcellus formation.
And as the wells multiply all along the western end of the state, people worry they may be facing another toxic legacy.
The first one came from coal mining. All over the state, you can see bright orange rivers and streams. The aquatic life was killed by acidic runoff from abandoned mines.