Today scientists know even more about the shale rock formation. Although the Marcellus is probably the best known, it's actually sandwiched between two other formations, the Upper Devonian and Utica, which further magnifies the potential of the entire area. This area "seems to be a geologic overlap of all the major shale plays, so it's almost like a triple play here. That's what's exciting," Zagorski says. "I bet we haven't even scratched the surface of 5 to 10 percent of this yet as an industry."
The sheer magnitude of the reserves of natural gas found across the various shale plays in the United States—potentially a 100-year supply depending on consumption, according to some estimates—puts the country at a distinct advantage as a player in the global energy market. Industry leaders have gone from puzzling over ways to import natural gas and other fuel sources just a few years ago to scrambling to retrofit facilities to export the fuel to energy-hungry countries abroad. Where Congress was once discussing incentives for more ultra-deepwater drilling in the Gulf to extract more energy resources, they and industry leaders are now facing a different problem: too much natural gas, which has driven down the price to historic lows. All of this has "the potential to literally change the geopolitical construct around energy and the power shifts that result from that," Klaber says.
The increased development of the Marcellus is expected to contribute $42.4 billion annually to Pennsylvania's economy by 2035—up from just $7.1 billion in 2010—according to financial analytics firm IHS Global Insight, and job growth in the region has been some of the best in the nation. Landowners whose property goes for as much as $5,000 an acre have made a windfall from leasing to natural gas development companies. Still, some politicians' plans to turn Pennsylvania into the "Texas of the natural-gas boom" don't sit well with some environmentalists and local residents.
Since operations have ramped up in the Marcellus, there's been no shortage of complaints about air pollution, spills, and potential contamination of drinking water. Pennsylvania has made many strides in regulations to allay some of the public's fears, including updating well standards and hiring more staff to deal with the influx of permit applications.
But it's really the water—about 4 million to 5 million gallons per frack job—and chemicals used in hydraulic fracturing that continues to be a sticking point among critics. Although the chemicals make up only about 0.2 percent of the fracking fluid, environmentalists continue to be concerned about the potential for the mixture to contaminate surrounding groundwater.
But it's not so much what's happening deep underground that worries some opponents, it's the impact it's having on communities in the thick of the push to dramatically increase well drilling and natural-gas production in the Marcellus. Jobs might be up and local economies booming, but there are also trucks roaring down what were once quiet, peaceful country roads. Gas companies such as Range Resources are trying to minimize the impact of drilling operations in local communities by increasing communication and buy-in from residents who are affected as well as repaving roads used frequently to transport equipment, but there's still a human cost to the natural-gas boom. "This is the sacrifice zone," says Terry Engelder, a Penn State geologist who's studied the Marcellus Shale formation for decades. "You have to put up with truck traffic noise, but it's a matter of industrialization and doing business."