Three U.S. House members investigating the use of toxic substances in the fluids injected into natural gas wells have revised their estimate of the amount of diesel fuel used in the practice, known as hydraulic fracturing or "fracking."
Rep. Henry Waxman of Los Angeles, the ranking Democrat on the House Energy and Commerce Committee, joined Edward J. Markey (D-Mass.) and Diana DeGette (D-Colo.) in sending a letter to the Environmental Protection Agency.
The letter said two companies had erroneously reported usage of diesel fuel in fracking fluids, which are injected at high pressure into rock formations — usually shale — to create fissures that allow natural gas to be extracted.
More than 32 million gallons of diesel were used from 2005 to 2009 by 12 companies employing fracking in states including Texas, Oklahoma, Louisiana, Colorado, Wyoming, North Dakota, West Virginia and Pennsylvania, among others.