Hydraulic fracturing is a process for improving oil and gas extraction from subsurface formations that prove too tough for traditional drilling techniques. Rocky shale formations are prime candidates for , hydr
aulic fracturing, or ‘fracking’. In the US, many of these sites are located in the rural Midwest or Appalachia.
The process of fracking is unique from most other extraction methods.
Typically, water, sand, and a small amount of chemical additives are pumped deep beneath the ground (as much as 10’000 feet) under high pressure. This forces new cracks in the subsurface strata due to the volume and pressure of the injected water; the sand is then used to wedge the new cracks open, forming easier access 
paths for oil and gas to escape back up the bore hole towards the surface.
A side affect of this process is the violent disruptions of the subsurface strata. This is a source of concern for residents that live in communities where fracking occurs. Allegations of ground water contamination as well as other ills have dogged the methodology since it’s introduction.
However, as several Department of Energy and EPA studies have found no specific evidence to support these claims. Activists counter that the EPA adn DOE performed studies too narrow in scope to get a full view of what’s the industry is actually doing.
With number of stories growing of children growing sick in areas where intensive fracking is occuring or contaminated groundwater sickening residents. Many that live in these regions are hard-pressed to take either the governments studies or the industries words of care and concern at face value.
Further, some of the oil deposit estimates that helped fuel the push towards fracking are beginning to unravel, such is the case with the Monterrey Oil Shale in California, which EPA officials estimate may need to be revised downward by 96%.
At the end of the day, two things can be said: Oil exploration, even fracking, is a very profitable business, and without clear and concise proof of it’s danger. It will likely remain so well into the future.
Sources:
http://www2.epa.gov/hydraulicfracturing
http://energy.gov/fe/articles/netl-releases-hydraulic-fracturing-study
http://energyindependence.michamber.com/energyindependence/what-hydraulic-fracturing
http://www.latimes.com/business/la-fi-oil-20140521-story.html