As noted in the Federal Register (79 FR XXXXX, February 12, 2014), the U.S. Environmental Protection Agency (EPA) has released an interpretive memorandum to clarify Underground Injection Control (UIC) program requirements under the Safe Drinking Water Act (SDWA), as amended by the Energy Policy Act of 2005, for underground injection of diesel fuels in hydraulic fracturing (HF) for oil and gas extraction and a technical guidance containing recommendations for EPA permit writers to consider in implementing these UIC Class II requirements. The EPA has developed the memorandum and technical guidance to achieve the following objectives: 1) to explain the existing legal requirement under the 2005 statutory amendments to the SDWA and the EPAs implementing regulations regarding applicability of UIC program permitting requirements, that any owner or operator who injects diesel fuels in HF for oil or gas extraction must obtain a UIC Class II permit before injection; 2) to explain the agencys interpretation of the statutory term diesel fuels in hydraulic fracturing for oil or gas extraction as used in the SDWA; and 3) to describe existing UIC Class II program requirements for permitting underground injection of diesel fuels in HF and to provide recommendations for EPA permit writers to consider in implementing these requirements to ensure protection of underground sources of drinking water (USDWs).