U.S. Environmental Protection Agency (EPA MOA). 2003. A Memorandum of Agreement Between The United States Environmental Protection Agency and BJ Services Company, Halliburton Energy Services, Inc., and Schlumberger Technology Corporation: Elimination of Diesel Fuel in Hydraulic Fracturing Fluids Injected into Underground Sources of Drinking Water During Hydraulic Fracturing of Coalbed Methane Wells, Dec. 12, 2003.
"While the Companies do not necessarily agree that hydraulic fracturing fluids using diesel fuel endanger USDWs when they are injected into CBM production wells, the Companies are prepared to enter into this agreement in response to EPA’s concerns and to reduce potential risks to the environment." See Drilling Around the Law for a follow-up on this voluntary agreement. According to the Environmental Working Group's report, "This promise, however, applied to only coalbed methane wells -- a small portion of natural gas and oil wells drilled – and only to those drilled directly into underground sources of drinking water."