Advocacy groups claim energy policies aren't strict enough for hydraulic fracturing. The EPA last week issued draft permitting guidance for wells that use diesel fuels during hydraulic fracturing, known also as fracking.
"EPA developed the draft guidance to clarify how companies can comply with a law passed by Congress in 2005, which exempted hydraulic fracturing operations from the requirement to obtain an underground injection control permit, except in cases where diesel fuel is used as a fracturing fluid," the agency said in a statement.
Michael Brune, executive director of the Sierra Club, complained that diesel has no place in natural gas extraction methods that pose a threat to drinking water supplies.
"Diesel and drinking water don't mix," added Jennifer Krill, executive director of advocacy group Earthworks, in a statement.
Fracking employs a mixture of sand, water and trace chemicals to extract natural gas from underground shale deposits. The United States has some of the richest deposits of shale natural gas in the world, though critics worry some of the chemicals found in fracking fluid could find their way into drinking water.