Hydraulic fracturing involves injection of large volumes of fluids at high pressure into a well to create fractures in the source rock formation. This technique was designed to improve oil and gas production. Hydraulic fluids that are used in this technique are a mixture of water, chemical additives and proppants (small spheroids of solid material). The types of concentrations of chemical additives and proppants used in hydraulic fracturing fluids vary depending on site-specific conditions and are usually tailored to needs of the project. In some instances, operators will use diesel fuels as an additive. Diesel fuels may contain a number of chemicals of concern including benzene, toluene, ethylbenzene and xylene compounds that are highly mobile in groundwater.

Underground injection of fluids through a well is subject to the requirements of the Safe Drinking Water Act (SDWA). In the 2005 Energy Policy Act, Congress revised the SDWA definition of “underground injection” to specifically exclude hydraulic fracturing fluids from the Underground Injection Control (UIC) program, except in instances where diesel fuels are used as an additive. [SDWA section 1421(d)(1)(B)]. Thus, owners or operators who inject diesel fuels for hydraulic fracturing related to oil and gas operations must first obtain a UIC permit before the injection begins.

On February 12, 2014, the United States Environmental Protection Agency (“EPA”) released an interpretive memorandum to clarify the UIC program requirements under the SDWA, for underground injection of diesel fuels in hydraulic fracturing for oil and gas extraction. The agency has also released technical guidance containing recommendations for EPA permit writers to consider in implementing the UIC requirements.

According to the Louisiana Department of Natural Resources, there are no known operations in Louisiana that inject diesel fuels for hydraulic fracturing at this time. And although the technical guidance was developed specifically for hydraulic fracturing where diesel fuels are used, many of the guidance’s recommended practices are consistent with best practices for hydraulic fracturing in general, including those found in state regulations and model guidelines for hydraulic fracturing developed by industry and stakeholders.

The EPA’s stated objectives are:

  •  To explain that any owner or operator who injects diesel fuels in hydraulic fracturing for oil or gas extraction must obtain a UIC Class II permit before injection.
  • To explain the agency’s interpretation of the SDWA statutory term “diesel fuels” for permitting purposes.
  • To describe existing UIC Class II program requirements for permitting underground injection of diesel fuels in hydraulic fracturing and to provide recommendations for the EPA’s permit writers to consider in implementing these requirements to ensure protection of underground sources of drinking water.

The guideline provides an overview of existing program requirements and technical recommendations pertaining to the following aspects of Diesel Fuels hydraulic fracturing permitting:

  1. Permit application submission and review process
  2. Information submitted with the permit application
  3. Wells authorized under permits
  4. Permit duration and well closure
  5. Area of review
  6. Well construction and mechanical integrity testing
  7. Well operations, monitoring and reporting
  8. Financial responsibility
  9. Public notification and environmental justice.

The interpretive memorandum and technical guidance documents can be found on the EPA’s website here.