Shell SA's exploration for shale gas in the Karoo will use a safe technique not known to harm the environment, a senior executive said. "The oil and gas industry has used this technique safely for more than 60 years," Graham Tiley, general manager for new ventures and international exploration at Shell, told the media in Johannesburg...The director of the US Environmental Protection Agency "could find no evidence of a link between fracking and water contamination", Tiley said.