FILE - In this Wednesday, April 15, 2009 file photo, an unidentified worker steps through the maze of hoses being used at a remote fracking site being run by Halliburton for natural-gas

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FILE - In this Wednesday, April 15, 2009 file photo, an unidentified worker steps through the maze of hoses being used at a remote fracking site being run by Halliburton for natural-gas producer Williams in Rulison, Colo. The oil and gas industry is trying to ease environmental concerns by developing non-toxic fluids for the drilling process known as fracking. But it’s not clear whether the fluids will be widely embraced by drilling companies. (AP Photo/David Zalubowski, File) less 

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Associated Press
Sun, Feb 3, 2013 6:50 PM EST