"Drilling service companies have injected at least 32 million gallons of diesel fuel underground as part of a controversial drilling technique, a Democratic congressional investigation has found.

Injecting diesel as part of 'hydraulic fracturing' is supposed to be regulated by U.S. EPA. But an agency official told congressional investigators that EPA had assumed that the use of diesel had stopped seven years ago.

'The industry has been saying they stopped injecting toxic diesel fuel into wells,' said Rep. Henry Waxman (D-Calif.), the ranking member on the House Energy and Commerce Committee, who led the inquiry. 'But our investigation showed this practice has been continuing in secret and in apparent violation of the [Safe Drinking Water Act].'"

Mike Soraghan reports for Greenwire January 31, 2011. [2]