DRILLING: Drilling for natural gas in Colorado's Piceance Basin.
FLICKR/ENERGY TOMORROW

DIMOCK, PA -- Norma Fiorentino’s drinking water well was a time bomb. For weeks, as workers drilled natural gas deposits nearby, stray methane worked into tiny crevasses in the rock, leaking upward into the aquifer and slipping quietly into her well. Then, according to the state’s working theory, a pump turned on in her well house, flicked a spark, and caused a New Year’s morning blast that tossed aside a several-thousand-pound concrete slab.

Afterward state officials found methane, the largest component of natural gas, in her drinking water.

Dimock, the poverty-stricken Susquehana County enclave where Fiorentino lives, is ground zero for drilling the Marcellus Shale, a prized deposit of natural gas touted as one of the most abundant and cleanest alternatives to oil. The drilling here is supposed to be a boon, bringing jobs and millions of dollars in royalties to cash-strapped homeowners.

But a string of documented cases of gas escaping into drinking water – in Pennsylvania and other states – is raising new concerns about the hidden costs of this economic tide and strengthening arguments across the country that drilling can put drinking water at risk.

Near Cleveland, Ohio, a house exploded after gas seeped into its water well. The Ohio Department of Natural Resources blamed a nearby gas well’s faulty cement casing and hydraulic fracturing – a deep-drilling process that shoots millions of gallons of water, sand and chemicals into the ground under explosive pressure – for pushing methane into an aquifer and causing the explosion.

In Dimock several drinking water wells have exploded and nine others were found with so much gas that one homeowner was told to open a window if he planned to take a bath. Dishes showed metallic streaks that couldn’t be washed off and tests also showed high amounts of aluminum and iron, prompting fears that drilling fluids might be contaminating the water along with the gas. In February the Pennsylvania Department of Environmental Protection charged Cabot Oil & Gas with two violations that it says caused the contamination, theorizing that gas leaked from the well casing into fractures underground.

Industry representatives say methane contamination incidents are statistically insignificant, considering that 452,000 wells produced gas in the United States last year. They also point out that methane is common in nature and can leak into water from biological processes like rotting plants.

The industry says its construction technology keeps gas and drilling fluids – including any chemicals used for hydraulic fracturing – safely trapped in layers of steel and concrete. Even if some escapes, they say, thousands of feet of rock make it almost impossible for it to migrate into drinking water aquifers. Those arguments helped the gas drilling industry win rare exemptions from the Safe Drinking Water Act and the Clean Water Act when Congress enacted the 2005 Energy Policy Act.