As drivers travel down Route 6 through Mansfield, Pa., they quickly realize something has changed about the rural town. Trailers for energy companies are popping up like mushrooms, and traffic has become increasingly snarled as trucks carrying material to and from natural-gas drilling sites share the road with local cars.

It's not quite a boomtown, but it is certainly changing, and the transformative agent over the past two years has been the discovery of an estimated 500 trillion cubic feet of recoverable natural gas locked in the Marcellus Shale Formation some 5,000 to 8,000 feet below the earth's surface.

The Marcellus Shale Formation spans 600 miles of the Appalachian Basin, from West Virginia and Ohio to the Northeast through Pennsylvania and New York. In terms of potential recoverable gas, it is considered one of the largest unconventional sources in the world, according to Travis Windle, spokesman for the Marcellus Shale Coalition, a group of firms involved in the Marcellus shale business.

Many experts agree that the Marcellus shale region's potential for natural-gas production is vast. But at what price?

The only economical way to extract the gas is through a controversial technique called hydraulic fracturing, or hydro-fracking. The technique involves blasting millions of gallons of water mixed with sand and a small amount of chemicals deep into the ground to create in the rock fissures that then release the natural gas. The process is extremely resource-intensive: A single well can require more than three millions gallons of water as part of its development process.

Environmental groups believe hydrofracking, as well as the entire process of drilling for natural gas near community drinking-water supplies, is slowly poisoning the land and creating a living nightmare for some residents who live near the gas production wells and compressor stations.

While industry sources claim the process is safe, the issue has generated an enormous amount of controversy, fueled largely by lawsuits, media reports and a 2010 award-winning documentary, “Gasland,” which documented health and environmental problems that the film associates with hydrofracking.

Meanwhile, engineering and construction firms are finding plentiful work in the burgeoning oil-and-gas exploration and production industry throughout the Marcellus shale region as well as at shale plays in other parts of the U.S. and the world. Further, enterprising firms are trying to find solutions to some of the thorniest problems the gas sector faces. Engineering firms may well find themselves at the heart of determining whether this gas sector continues to develop or public pressure brings future drilling to a standstill.

Part of the Equation

Obama administration officials have made it clear that they consider natural gas an important part of the nation's energy mix for the foreseeable future. At a March 30, 2011, White House briefing for reporters, Energy Secretary Steven Chu said, “The [natural gas] reserves, because of the ability to frack shale rock, have been increasing. We believe that it is possible to safely and responsibly extract natural gas, and the U.S. government remains committed to that.”

But some lawmakers question the wisdom of relying too heavily on a technology that many say is harmful to the environment and public health. In its fiscal 2010 budget report, Congress appropriated funds for a federal study to evaluate whether the process can indeed be performed safely and cause no long-term threat to the environment.

The Environmental Protection Agency is in the middle of conducting that study now, and it plans to release a preliminary report late in 2012.

Environmental groups say they are pleased the EPA is taking a hard look at hydrofracking. Dusty Horwitt, senior counsel for the Environmental Working Group, an environmental and public health advocacy organization, says, “What we really need is some rigorous scientific investigation.” He claims a 2004 EPA study conducted during the George W. Bush administration that ultimately concluded hydrofracking posed no lasting harm to the environment was “deeply flawed in large part because EPA conducted no on-the-ground testing—it was basically just a literature review.”

Environmental Minefield?

Those findings emboldened energy services and supporting firms to press forward. “It's like a gold rush out there,” says Vince Rice, president and CEO of Aaron Enterprises, York, Pa., referring to the development of the Marcellus shale region. Aaron Enterprises specializes in “trenchless” pipeline technologies, such as boring and directional drilling used by utilities and a variety of other industries.

However, environmental concerns have grabbed the attention of the media and the public. The Pennsylvania Land Trust reports that, between Jan. 1, 2008, and August 20, 2010, more than 1,600 violations by 45 Pennsylvania Marcellus shale drillers were identified by the Pennsylvania Dept. of Environmental Protection, including 1,056 with the potential to cause environmental harm. Violations included improper well casing, improper construction of wastewater impoundments and non-compliance with permitting requirements. The most serious violation was inadequate blowout prevention at a Clearfield County site, where, on June 3, 2010, one million gallons of gas and water shot 75 feet into the air for 16 hours.

The problems are not specific to Pennsylvania. Similar incidents have occurred at shale plays in Ohio and Colorado in recent years, and residents near compressor stations close to the Barnett Shale Formation in Texas have complained of air quality, says Horwitt.

Moreover, the contamination of water wells and drinking-water supplies has spawned several lawsuits, including one filed against Houston-based Cabot Oil in 2009 by several families from the small town of Dimock, Pa., who are now drinking bottled water after methane and metals allegedly leaked into local water wells and streams, poisoning the water supply.

Environmentalists say it is difficult to determine whether it is the hydrofracking or other mistakes in the drilling process that are causing spills, leaks and other hazards, but it is clear problems are occurring.

Jeff Schmidt, director of the Pennsylvania chapter of the Sierra Club, which has about 17,000 members throughout the commonwealth, says, “There are a lot of examples of problems that have occurred because of drilling [that took place] where, if they didn't have the fracking process, they wouldn't be drilling in those locations. … So, clearly, if we weren't fracking, we wouldn't have a lot of the environmental problems that we're seeing in the gas drilling of the Marcellus shale.”