National Public Radio: Environmentalists and the natural gas industry are getting ready for a battle in Congress over something known as "hydraulic fracturing." "Fracking," as the industry calls it, involves injecting a million gallons or more of water and chemicals deep underground to pry out gas that’s locked away in tight spaces. Environmentalists want the federal government to regulate the practice because, in some cases, fracking may be harming nearby water wells. The industry says regulation …