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Hydraulic Fracturing: Drilling for Answers

EPA researchers will study key aspects of the potential environmental and human health impacts of a technique used to drill for natural gas.

A natural gas drilling platform

Hugh Bases began camping with his dad and brothers on his uncle’s farm, a patchwork of pastureland, open meadows, and forest in the Catskill region of New York, when he was a toddler some 40 years ago. Now a developmental pediatrician and a dad himself, he enjoys bringing his young daughter and son to the farm to cookout, splash around in the pond, and camp under the stars. 

Recently, Dr. Bases has started to wonder if the farmland that has been in his family for going on three generations might be sitting on top of a lucrative natural gas reserve, making it far more valuable for the resource below than for the grass and space leased to a local dairy farmer.

“My ears really perked up when I began to hear that energy companies might be interested in leasing land in the area for natural gas development,” says Dr. Bases. “But I also know the area is part of New York City’s watershed, so I wondered if it was going to be allowed, or even appropriate.”

The farm is one of many properties in an area stretching from New York to Tennessee that are sitting above a subterranean geologic formation known as the Marcellus Shale. Geologists estimate that locked within the sedimentary rock some 6,000 to 8,000 feet below is one of the world’s biggest natural gas fields, containing enough energy to meet the natural gas needs of the entire United States for two full years.

A convergence of factors over the past few years have put the Marcellus shale and other areas once considered too deep or otherwise economically unfeasible into play for natural gas development. Rising energy prices, the need to expand domestic energy supplies, and an economic downturn that has hit rural areas particularly hard, have combined to spark a potential natural gas boom. What’s more, natural gas burns cleaner and emits less greenhouse gas per unit of energy than other fossil fuels.

With those factors already in place, a drilling technique known as hydraulic fracturing—“fracking” for short—has made it both possible and profitable to unlock natural gas reserves from deep, rocky geologic formations, such as the Marcellus shale, found in many areas of the country.

The key component of hydraulic fracturing, and what gives the technique its name, is creating or enlarging cracks in subterranean rock formations. Drill shafts are sent deep into the ground. Then, large quantities of water (millions of gallons per well), along with chemicals and “proppants” (sand, ceramic beads, or other small particles that hold open the cracks) are injected into the shaft at high pressure, cracking open fissures into rock. The proppant holds the fissures open, allowing the natural gas to flow into the well shaft where it can flow up to the surface.

Drilling, together with injecting water, sand, and chemicals has provided a technological solution to the challenge of harvesting natural gas from deep underground rock formations.

But the practice of hydraulic fracturing has raised questions about its potential impact on the environment and human health, particularly on water quality and drinking water:

  • What impact does removing the large amounts of water needed for high-pressure drilling have on a watersheds and aquifers?
  • What are the potential impacts of the chemicals and drilling muds used in drilling and the hydrofracturing process, wastewater, and fractured geology have on water quality and underground drinking water supplies?

At the request of the Congress, researchers at the U.S. EPA are gearing up to provide the science needed to answer these and other questions related to hydraulic fracturing.

“Our research will be designed to answer questions about the potential impact of hydraulic fracturing on human health and the environment,” said Paul T. Anastas, Ph.D, the Assistant Administrator for EPA’s Office of Research and Development. “The study will be conducted through a transparent, peer-reviewed process, with significant stakeholder input.”

Still in the early stages of developing a strategic research plan, EPA scientists, engineers, and science policy experts are working together to define the most pertinent research questions, identify gaps in existing data, build a robust process to incorporate stakeholder input, and identify research priorities.

Once a detailed study design is developed it will undergo external scientific peer review before research activities are implemented. 

EPA’s Office of Research and Development produced Scoping Materials for Initial Design of EPA Research Study on Potential Relationships Between Hydraulic Fracturing and Drinking Water Resources, a document to elicit ideas and suggestions from the EPA Science Advisory Board (SAB). The SAB is an independent, external federal advisory committee called upon to provide expert council to the Agency regarding technical matters.

The SAB has been working to advise EPA on the scope of a hydraulic fracturing study, identify key research questions, and provide input for making stakeholder involvement an integral component of the research program.

Once the SAB’s recommendations are incorporated together with input from stakeholders, the Office of Research and Development will conduct key studies focused on high priority research questions. It is anticipated that research will begin during 2011, with initial outcomes and research products available by the end of 2012.

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