Using pressurized fluids to crack rocks to extract natural fossil fuels is called hydraulic fracturing, or fracking.  The process is used to extract oil or gas from impermeable or tight geologic formations, such as shale rock formations and tight sands.  The pressurized fluids, including water and chemical additives, open or enlarge fractures in the rock.  Sand or other material is then pumped into the fractures to keep the fractures open.  The water and chemical additives are returned to the surface and gas flows from pores and fractures in the rock into an existing well for extraction.

While the process has been used since the 1940s in the US to increase production from oil wells, it is now increasingly being used to extract gas from shale formations.  Concerns are rising about the threats to groundwater and public health from the chemicals in the fluids.  In the United States, there have been reported instances of groundwater contamination and illnesses from the fracking and the US Environmental Protection Agency (EPA) is currently carry out a research project to determine the nature and scope of any risks associated with fracturing.

Some further ideas to explore on Hydraulic Fracturing:

See if you can find any data or information on what chemicals are used by the gas extraction industry in fracking and what risks there are from those chemicals.

If you cannot find information or data, what issues does that create for assessing the impacts from fracking?


“Hydraulic Fracturing,” US EPA at

Mark Zoback Saya Kitasei Brad Copithorne, Addressing the Environmental Risks from Shale Gas Development, Worldwatch Institute, July 2010

“Philadelphia seeks ban on hydraulic fracturing,” Reuters/ENN News, March 26, 2010

Update: 27 Feb 2011

“Regulation Lax as Gas Wells’ Tainted Water Hits Rivers,”  The New York Times, 27 February 2011.

Update: 1 Nov 2011

Osborn, SG, A Vengosh, NR Warner, RB Jackson, “Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing.” Proceedings of the National Academy of Sciences (May 17, 2011).

Robert B. Jackson, Brooks Rainey Pearson, Stephen G. Osborn,

Nathaniel R. Warner, Avner Vengosh, Research and Policy Recommendations for Hydraulic Fracturing and Shale-Gas Extraction (Duke University)

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One comment so far, add your own below

  • 28 Jun 2012 at 5:32 pm Newtec

    These Fracking Companies need to be regulated. The water spuply will be destroyed if they keep drilling for Natural Gas with these TOXIC CHEMICALS. Not to mention the Toxic Plumes we are breathing. They are paying these poor farmers and land owners to use their land to make profits at any cost. How do we let them drill for oil in our oceans and have the accidents like in the Gulf. They will run wild if let be. Profits is what matters to these Companies. Lets force them to be responsible and not use these Toxic Chemicals. As far as I know, only water and sand was used in the old days. I’d like to know if these chemicals are also being used in our oceans. We the People Need to Stand Up!!!!!!!

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