The gas stored in the Marcellus Shale formation is the subject of desperate drilling to secure US domestic energy supplies. But the process involved - hydraulic fracturing - is the focus of a bitter dispute over environmental damage and community rights.

It is a timeless patchwork of small dairy farms and endless hills, emblazoned with the blood-red tints of an autumnal Pennsylvania forest. Set against this sleepy backdrop, however, the constant convoys of water trucks rumbling along the deserted country roads suggest something profound is taking place. This is ‘fracking’ country, the latest frontier in America’s desperate search for fossil fuels.

Pioneered by companies such as Halliburton, high-volume horizontal slickwater fracturing – otherwise known as hydraulic fracturing, or simply fracking – involves the drilling of horizontal wells that are then injected with large volumes of water, sand and chemicals at high pressure to open up rock fractures and help propel rock-trapped gas back to the surface.

Professor Anthony Ingrafea, one of the world's leading experts on fracture mechanics, based at Cornell University, told the Ecologist:

...there is an overriding urgency to slow down the fracking rush. 'I'm not anti-oil and gas. What I'm against is an industry that is so out of control in using a new technology that does not have proper regulation, and enforcement of regulation, that they're riding roughshod over a large segment of the population.'