Last week, the United States Environmental Protection Agency released its draft Underground Injection Control (UIC) Program Guidance for Class II wells that utilize diesel fuel as a fracturing fluid or as a component of a fracturing fluid in hydraulic fracturing operations. The draft guidance provides recommendations for UIC permit writers related to permit duration and well closure, permit application and review, area of review, and well construction, including mechanical integrity testing, financial responsibility, and public notification. The draft guidance identifies the following six substances by their chemical abstract service (CAS) numbers, which would trigger Safe Drinking Water Act (SDWA) requirements if injected as a component of hydraulic fracturing fluid: 68334-30-5, 68476-34-6, 68476-30-2, 68476-31-3, 8008-20-6, and 68410-00-4. According to the fact sheet for the draft guidance, it is “intended to provide information for EPA permit writers issuing permits under the Safe Drinking Water Act (SDWA) to ensure protection of underground sources of drinking water (USDWs).” The draft guidance is open for 60 days for public comment. In the interim, while this guidance undergoes public notice and comment, EPA expects that permitting decisions concerning hydraulic fracturing operations that use diesel fuels will be made on a case-by-case basis. EPA further expects that the draft guidance will not be cited as a basis for such permitting decisions.