The EPA on Tuesday released its final guidance document for permitting of hydraulic fracturing operations when diesel fuels are added to the fracking fluid. The guidance is intended to be used by EPA permit writers administering the Safe Drinking Water Act’s Underground Injection Control (UIC) Program.  Hydraulic fracturing was exempted from the jurisdiction of UIC in the Energy Policy Act of 2005, except when diesel fuels are used in the process. An interpretive memorandum issued along with the guidance applies the permitting requirements for Class II wells in the UIC program to wells where hydraulic fracturing is used, but also gives permit writers discretion to use alternative approaches that are consistent with regulatory and statutory requirements.

The guidance was criticized by industry and state officials because it is duplicative of effective state regulation of the practice, and unnecessary because diesel fuel had already been largely phased out of use in hydraulic fracturing operations. Industry officials have indicated that it would be possible for them to avoid using diesel fuels altogether in fracking fluids, but that the overly broad definition of “diesel fuels” used in the guidance precludes this. The EPA concurred that diesel fuels are used in a relatively small proportion of hydraulic fracturing wells, and less than 2% of wells were found to have used them in the agency’s review of FracFocus.

The definition of “diesel fuels” used in the guidance is based on Chemical Abstracts Service (CAS) registry numbers that encompass similar materials known as automotive diesel fuels, catalytic cracker feedstock, distillate fuel oils, heating oil, jet fuel, kerosene, marine diesel fuels, and No. 4 fuel oil. The registry numbers for these substances are CAS 68334-30-5, CAS 68476-34-6, CAS 68476-30-2, CAS 68476-31-3, and CAS 8008-20-6. Several environmental groups were advocating for exceptionally broad definitions of diesel fuels to essentially encompass all petroleum distillates.

The guidance did not include any “de minimis” limit on applicability. The lack of a de minimis threshold is significant as it could potentially be used by aggressive permit writers to require UIC permitting for trace levels of diesel not intentionally added to the hydraulic fracturing fluid.