The Environmental Protection Agency’s science advisors meet today to begin studying the impacts on drinking water of the gas drilling practice known as hydraulic fracturing.

While the gas industry argues that the chemical-infused technique is perfectly safe and vital to reaching vast gas supplies, concerns about its potential impact on water supplies is spreading outward from New York, where an environmental review process has held up gas drilling in parts of the Marcellus Shale, a gas-rich formation that underlies several states including Pennsylvania, Ohio and West Virginia.

The city of Philadelphia is also now attempting to block gas drilling near the Delaware River watershed, which supplies about half of the city’s tap water. The City Council unanimously passed a resolution in late March that calls on the Delaware River Basin Commission to deny any hydraulic fracturing permits.

Hydraulic fracturing, or fracking, involves injecting large quantities of water along with secret mixes of chemicals deep underground in order to break up gas-containing rock formations. The technique has been used for decades, but in the Marcellus Shale region, it is combined with horizontal drilling and other methods that environmentalists fear could pollute groundwater sources and cause severe problems downstream.

“The EPA study is a really great start to answer some questions,” said Erika Staaf, clean water advocate for the non-profit PennEnvironment. “If drilling is moving forward, which it is, we want to make sure that it happens in a way that fully protects the environment, aquatic life, habitats, our forests and public health.”

Pennsylvania Fracking

Fracking is already under way in parts of Pennsylvania, and oil and gas companies such as Exxon and BP are lobbying Congress to keep all potential obstacles — including regulators — out of the way. The Marcellus Shale holds about 350 trillion cubic feet of natural gas — enough to keep the country going for 15 years at present consumption rates.

“Ideally, what they would be doing is either slowing down the drilling or stopping the drilling until they have a better sense of what the science is,” said Deborah Goldberg, a managing attorney with Earthjustice’s Northeast office.

“There have been no signs of that happening in Pennsylvania, and in New York, it’s happening only because of the environmental review process, and when that’s over, we expect there will be huge pressure to drill.”

So far, most of the documented connections between fracking fluid and drinking water involve individual wells. In Western Pennsylvania, however, there is some indication of larger dangers.

During drought conditions in the summer of 2008, a drinking water advisory was issued covering about 350,000 people in the Pittsburgh area citing high levels of “total dissolved solids,” or TDS, in tap water coming from the Monongahela River. TDS can cover a number of substances, including salts and some potentially more dangerous chemicals.

The Pennsylvania Department of Environmental Protection listed a number of potential sources — including increases in “non-conventional drilling.” The DEP instructed sewage treatment facilities that had been accepting wastewater from fracking wells to reduce the amount they treated, from 20 percent of the total down to 1 percent.

Elsewhere, fracking projects in Wyoming have apparently resulted in contamination of some drinking water wells, although officials said the presence of chemicals like 2-butoxyethanol could come sources other than gas drilling. Pittsburgh’s TDS levels remain the only documented case of a large water supply with contamination potentially associated with hydraulic fracturing.

Drilling companies generally keep the contents of their “fracking fluid” private, but mixtures of chemicals including benzene and other carcinogens have been used. Wastewater from wells can contain traces of those chemicals as well as naturally occurring substances that are pulled up from deep underground; these tend to include salts, and wastewater has been found to be as much as five times as salty as seawater.

Will Study Lead to Regulation?

Goldberg said it is unlikely that the EPA will step in and strictly regulate fracking in the Marcellus Shale area, in spite of the study starting now.

“To do a really serious study of the impacts on drinking water is a monumental undertaking, because it really requires some very serious hydrological studies that either are not being done or are being done only by industry and are not being shared,” she said, adding that if drilling near the Delaware River’s headwaters does move forward, drinking water could be at risk in New York and Philadelphia.

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