November 27, 2013 11:00 PM

Fracking requires chemicals and water, raising unresolved claims about pollution

Fracking, the controversial drilling technique that is driving America’s energy boom, has been around for decades. But it was only in the last decade that the process of blasting underground rocks with water and chemicals was refined enough to deliver a long sought oil and gas bounty and stir a furious debate over its health and environmental consequences.

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