On February 11, 2014, the Environmental Protection Agency (EPA) issued a final Permitting Guidance for Oil and Gas Hydraulic Fracturing Activities Using Diesel Fuels: Underground Injection Control Program Guidance #84,” replacing a draft Guidance dated May 2012. The EPA has authority under the Safe Drinking Water Act (SDWA), as amended by the 2005 Energy Policy Act, to regulate hydraulic fracturing operations that include diesel fuels in the fracking fluids. Under the EPA’s Underground Injection Control (UIC) program, hydraulically fractured wells are considered Class II wells that must be permitted before injection can begin. The EPA has issued this Guidance “to alleviate uncertainty regarding the applicability of UIC Class II permitting requirements and the agency’s interpretation of the term ‘diesel fuels’ in the statute.”  

The Guidance defines “diesel fuels” in terms of five specific Chemical Abstract Services Registry Numbers: 68334-30-5, 68476-34-6, 68476-30-2, 68476-31-3, and 8008-20-6, which categories include vehicular diesel fuels, diesel fuel oil, heating oil, marine diesel fuel, deodorized kerosene, and jet fuel, among many others. With diesel fuels, the EPA’s main concern is that they may contain benzene, toluene, ethylbenzene, and xylene compounds (BTEX), which are highly mobile in ground water. The EPA has set maximum contaminant levels for each compound.

While the Guidance sets out recommended practices for hydraulic fracturing operations where diesel fuels are used, the EPA suggests that these practices are “consistent with best practices for hydraulic fracturing in general, including those found in state regulations, voluntary standards from the American Petroleum Institute (API), and model guidelines for hydraulic fracturing developed by industry and stakeholders.” Included in the best practices are:

  • The EPA UIC permit writer should consider information about (a) the extent and orientation of the planned fracture network, any nearby underground sources of drinking water (USDWs) and their connections to surface waters, (b) seismic history, (c) baseline geochemical parameters on accessible USDWs and other subsurface formations, and (d) anticipated true vertical depths of the formations to be hydraulically fractured and the anticipated pressure range for the proposed fracturing activities.
  • Water monitoring may be needed for permits that run shorter than the full life of the well.
  • The wells must be cased and cemented in a manner that prevents the movement of fluids into or between USDWs for the life expectancy of the well.
  • In determining casing and cementing requirements, consideration should be given to the geology of the injection and confining zones, the depth between the injection zone and water sources, and proposed injection pressures.
  • Additional testing may be needed to ensure that the well maintains mechanical integrity before, during and after the use of diesel fuels in hydraulic fracturing operations.