EPA to probe gas drilling's toll on drinking water

The Environmental Protection Agency on Thursday released the outlines of its long-awaited probe into whether hydraulic fracturing — the unconventional drilling technique that's led to a boom in domestic natural gas production — is contaminating drinking-water supplies. Investigators will try to determine the impact of large-scale water withdrawals, aboveground spills of drilling fluids, and the fracturing process itself on water quality and quantity in states where tens of thousands of wells have been drilled in recent years. Hydraulic fracturing, or fracking, involves the high-pressure injection of millions of gallons of water, along with sand and chemical additives, deep underground to extract natural gas trapped in shale rock. Energy companies have greatly expanded their use of fracking as they tap previously unreachable shale deposits, including the lucrative Marcellus Shale formation in Pennsylvania and neighboring states. The industry has long contended that fracking is safe, but environmentalists and some residents who live near drilling sites say it has poisoned groundwater. The EPA study, mandated by Congress last year, is the agency's first look at the impact of fracking in shale deposits...more