(Earth Focus: Episode 52) U.S. domestic gas production is on the rise because of hydraulic fracturing, or fracking, a controversial method of extracting natural gas from shale rock by pumping millions of gallons of water mixed with sand and chemicals underground at high pressure. Environmentalists say this gas boon threatens water supplies and pollutes air. Now, as fracking expands around the world, so does growing resistance. "Earth Focus" looks at three countries on the new fracking frontline: South Africa, Poland, and the UK. Reported from South Africa by Jeff Barbee and Andrew Wasley from Poland and the U.K.