Since 2008, natural gas drilling crews have been flocking to Marcellus Shale, a large rock bed that lies about 6,000 feet beneath New York, Pennsylvania, West Virginia, and Ohio. Geologists say it could be the most productive natural gas field in the U.S., capable of supplying the entire country’s natural gas demand for up to two decades.

However, the drilling technique used to unlock the gas, called hydraulic fracturing, or “fracking,” has become a serious point of contention. 

Pioneered by Halliburton in the 1940s, fracking is a common process used by oil and gas companies to retrieve tough-to-get reserves. Much like bubbles in carbonated soda, natural gas exists in bubbles deep underground. Getting to these pockets involves injecting millions of gallons of water, sand, and chemicals into the ground to crack open these bubbles, allowing the gas or oil to flow to the surface.

While drilling companies are not required to disclose exactly what chemicals they use, experts agree that benzene, formaldehyde, methanol, and xylene, among others, are some of the most commonly used. All of these substances are toxic in water at very low levels.

    
Although fracking is the most efficient and widespread drilling method, used in about 90 percent of U.S. oil and gas wells, environmentalists and health advocates have raised concerns about potential health risks associated with the chemicals used in fracking.

According to a report released in November 2009 by Environment Texas, a research and policy group, gas drilling can pollute and sometimes poison clean water sources. 

 
“Fluid that is left behind (some studies estimate that 91 percent of injected fluid never returns to the surface) after the fracking process could find its way to drinking water,” the report says, “and drilling into these formations can create pathways by which fluids or natural gas itself can find its way into water supplies.”

The protests of advocacy groups and concerned citizens have sparked a national debate. 

Does oil and well drilling contaminate drinking water?

People living near drilling facilities in states like Pennsylvania, Colorado, New Mexico, and Wyoming seem to think the answer is yes.

“We always had beautiful water, then we lost water completely the day they drilled–and when it came back, it was murky, salty, bubbly and smelly,” Ohio residents Mark and Sandy Mangan told Cleveland.com last week.

To the west, Wyoming residents are experiencing the same thing. Louis Meeks, a 59-year-old alfalfa farmer, is convinced that energy companies drilling for natural gas in his central Wyoming farming community have poisoned his water. According to Meeks, the water from his tap contains an oily glisten and smells like paint. Meeks, who suffers from pulmonary hypertension and neuropathy in his legs, believes the unnatural looking water has ruined his health.

“They have ruined my life,” he told Reuters. “I would like to get out of here.” One thing is preventing him from leaving, though–his house is worth next to nothing. The value of his home has been undermined by water contamination, a realtor told Meeks, and his house is now worthless.

Industry representatives, on the other hand, have staunchly denied allegations. Rick Simmons, spokesman for the Ohio Department of Natural Resources, refuted the Mangans’ claims, pointing the finger instead at mild drought conditions in parts of Ohio that year.

“There is absolutely no evidence of a link between the drilling and their well problems,” he said in a statement, citing a report from Energy in Depth, a coalition of independent gas producers.

Smarting from grassroots complaints and pressure from legislators, gas drilling advocates say the industry is using the latest and safest technology to keep fracking safe.

“The fluids used in the process are made of 99.5 percent water and sand – with the slight remainder comprised of household materials you’re just as likely to find in the kitchen cupboard and beneath the kitchen sink,” wrote Lee Fuller, director of a Energy In Depth, in a letter to Cleveland.com.

The drilling industry dismisses any claims that extracting gas from 4,000 feet below the earth could crack an aquifer or in any way threaten water supplies, which are often found within 100 to 300 feet below the surface.

“There’s already 3,500 feet in some cases of rock between the groundwater and where you get the oil and gas and that’s a formidable barrier,” said Tom Stewart, executive vice president of the Ohio Oil and Gas Association. “If they were failing everywhere, we’d know it.”

Stewart and others in the industry often refer to a 2004 EPA report that concluded hydraulic fracturing did not threaten the safety of groundwater used for drinking. 

  
Though the EPA has failed to conclusively connect fracking with the contamination of a particular well or region, prodding by the U.S. House of Representatives has led to further exploration. The EPA is currently investigating Louis Meeks’ native town of Pavillion, WY, where residents have long been suspicious of the local drinking water. Many experts are predicting that Pavillion, a town of less than 200, may become the center of the controversial drilling practice. Tests conducted late last year by the EPA found nearly a third of the wells to be contaminated, and although the federal agency did not identify the cause, it said gas drilling was a strong possibility. The EPA’s report is expected out sometime this spring.

Photo:  Courtesy National Energy Technology Laboratory (NETL), Department of Energy