The United States Environmental Protection Agency (“EPA”) and Air Alliance Houston and other environmental organizations (collectively “Air Alliance”) entered into a Consent Decree addressing emission factors for volatile organic compounds (“VOCs”) from certain natural gas production site flares.

The natural gas production sites are encompassed by the Clean Air Act Source Category entitled “Crude Oil and Natural Production, Transmission and Distribution” (“ONGs”).

Air Alliance had filed suit against EPA alleging that the agency failed to perform nondiscretionary duties under the Clean Air Act. These nondiscretionary duties allegedly involved a failure to review and, if necessary, revise the emissions factor for VOCs from elevated flares and enclosed ground flares in the ONG category at least once every three years.

An emission factor is a representative value that attempts to relate the quantity of a pollutant released to the atmosphere with an activity associated with the release of that pollutant. Emission factors can facilitate estimation of emissions from various sources of air pollution. They are typically averages of all available data of acceptable quantity, and are generally assumed to be representative of long-term averages for all facilities in the source category.

For purposes of the Consent Decree, “natural gas production sites” are defined as:

. . .the wells and all related processes used in the extraction, production, recovery, lifting, stabilization, separation or treating of natural gas (including condensate). “Natural gas production sites” include not only the pads where the wells are located, but also include stand-alone sites where natural gas (including condensate and produced water) from several wells may be separated, stored and treated.

Natural gas production sites are the only ONG source category for which EPA has and maintains an existing VOC emissions factor for flares. This VOC emission factor is included in EPA’s WebFIRE database.

Air Alliance alleged that EPA had not conducted a review of the natural gas VOC emission factors or revised this factor under Section 130 of the Clean Air Act in over three years.

The Consent Decree provides that EPA agrees that for the natural gas VOC emissions factor for elevated flares and enclosed ground flares at the natural gas production sites in the ONG source category, the agency shall:

  1. no later than June 5, 2017, review and either propose revisions to the Natural Gas VOC emissions factor under CAA section 130, 42 U.S.C. § 7430, or propose a determination that revision of the Natural Gas VOC emissions factor is not necessary under CAA section 130.
  2. no later than February 5, 2018, issue final revisions to the Natural Gas VOC emissions factor under CAA section 130, or issue a final determination that revision of the Natural Gas VOC emissions factor is not necessary under CAA section 130.

EPA further agrees that it will post the proposed revision or determination and the final revision or determination on its AP-42 website on the dates referenced in paragraph 2 of the Consent Decree.

A copy of the Consent Decree can be downloaded here.