Economist: How safe is fracking?

DOZENS of protesters, including a member of parliament, were arrested on August 19th during demonstrations around Britain against hydraulic fracturing, or fracking. Green campaigners targeted the offices and drilling sites of Cuadrilla, an energy company, which had to suspend its operations. Fracking has attracted protests everywhere from North and South America to Australia .Several European countries have banned the practice altogether . But how does fracking work, and how dangerous is it really?

By the 1970s America’s energy industry seemed to be in terminal decline. The oil majors had long ago gone abroad in search of richer fields. But a technique invented in the 1940s and adapted decades later by George Mitchell , a Texan oil man, could unlock the oil and gas reserves trapped in shale rock. Mr Mitchell found that by injecting water, sand and chemicals into the ground at high pressure he could fracture the rock and create pathways for the trapped oil and gas to escape. Light regulation and government subsidies have seen fracking take off in America. Shale beds now produce a quarter of the country’s natural gas, up from only 1% in 2000. By last year the price of gas in America had fallento about a quarter of that in Europe and a sixth of that in Asia, though it has since risen.  MORE