Some insist Marcellus Shale natural gas is a huge economic boom for America, while others are certain it's an environmental catastrophe.

Gas drilling from the Marcellus pollutes groundwater, or it never pollutes groundwater. It's cleaner than coal or oil, except that it's dirty. It provides a boost to hard-hit rural economies; but then again, maybe it doesn't.

The one point of agreement? Scientists say advocates on both sides increasingly spin every shred of research to fit their own views, and ignore the bigger picture. Read more »