By William Ecenbarger
Centuries ago only pine-coned Native American footpaths laced through the virgin forests of
But now the restful contours of the timbered mountains are once again being disturbed by economic interests. This time it is natural gas. Three- and four-acre drill pads are being carved out of virgin forest, 200-foot drilling rigs are rewriting the landscape, and caravans of water and gravel trucks are clogging roads originally designed for Model T Fords.
The visual assault, however, is not the biggest worry of environmentalists.
Hydraulic fracturing, or "fracking," the technique that has made the recovery of natural gas beneath the Marcellus Shale formation economically feasible, involves drilling a traditional vertical well of a mile or more-and then drilling out horizontally for another mile or more. The shale has to be broken for the gas to escape, and this is achieved by the high-pressure injection of water, sand and chemicals to break up the black rock.
This shale gas production process requires a lot of money. Each well costs about $3 million. But the drillers are betting their investments will pay off.
It also requires a lot of water, and the impact of large water withdrawals on streams and aquifers is what most concerns environmentalists-especially since the water is treated with chemicals before it is injected into the wells to enhance its effectiveness. As the water is flushed through the rock, it also gathers natural elements, like sulphur and iron.
A flowback cocktail
The contaminated water that returns to the surface is called "flowback"-and the debate over the gas drilling centers on how to treat it. If it is not properly treated, the used water can harm fresh water ecosystems. Flowback is a cocktail of carcinogenic solvents, hydrochloric acid, lubricants, anti-corrosion agents and microbe killers. In most cases, the recovered water is stored in ponds, transferred to tanks and trucked to processing plants.
The agency most responsible for monitoring the drilling activity is the Pennsylvania Department of Environmental Protection, which issues permits and requires operators to provide information on the sources and locations of water to be used, the anticipated impacts of drilling on water resources, and locations of facilities where drilling fluids will be taken for treatment and disposal. 
Last October (2009) the department fined Cabot Oil and Gas Corp., Houston, $56,650 for three chemical spills at a drilling site in Susquehanna County. A dozen homeowners have filed suit against Cabot in federal court seeking damages for contamination of the drinking water from their wells from the same spill. Poisoned drilling wastewater has been blamed for a massive kill of aquatic life along
The other side of the environmental coin is that most energy experts believe that the increased use of natural gas, which produces lower greenhouse emissions than coal or oil, will reduce global warming. Natural gas, once the Rodney Dangerfield of the energy world, has suddenly gotten respect and become vital to the nation's energy strategy. It is seen as an important bridge between dirty coal and renewable alternatives.
Gas as clean energy
Electric utilities and other energy-intensive enterprises are rethinking their strategies for the future. Should coal power plants be retrofitted for gas? While natural gas is mostly used to generate electricity, it can also power vehicles and heat homes. Corporations with large vehicle fleets, like AT&T and United Parcel Service, are beginning to switch from petroleum-based gasoline to natural gas.
The idea of exploiting domestic resources to reduce
Some of the nation's leading environmentalists want
the intermediate step between "dirty coal" and renewable alternatives like wind and solar generators. "Natural gas is the cleanest of the fossil fuels," says Christopher Flavin, president of the Worldwatch Institute, an environmental think-tank. "Nobody's ever argued that. The big thing that's changed is that shale gas has now opened up as this enormous resource."
Even the environmental downside offers economic opportunity. Businesses are starting up for the sole purpose of treating the tainted wastewater.
While the exploration of the Marcellus Shale has transformed the national debate over generating electricity, closer to home there are major consequences for the economy and the environment. The challenges to scenic beauty and water supplies are formidable, but the financial benefits in terms of tax revenues, royalties, new jobs and new business are tantalizing in an era of high unemployment and tight government budgets.
For better and for worse, the Marcellus Shale will play an enormous role in the future of
William Ecenbarger is an award-winning reporter who often covers state issues.