BACT Background


SCAQMD published its first BACT Guidelines in May 1983, and a major revision in October 1988. On September 8, 1995, the SCAQMD Governing Board adopted new policies and procedures that established the Scientific Review Committee and updated cost-effectiveness procedures. On December 11, 1998, the Governing Board approved: (1) a new format for listing BACT determinations; and (2) a revised process for updating SCAQMD BACT Guidelines that complies with federal and state laws. On October 20, 2000, the Governing Board approved revisions to the New Source Review regulations that: 1) maintained the federal Lowest Achievable Emission Rate (LAER) requirement for major polluting facilities; and 2) established a minor source BACT (MSBACT) for non-major polluting facilities that will consider cost before making MSBACT more stringent.

The BACT Guidelines for major polluting facilities include:
  • Part A: Policy and Procedures for Major Polluting facilities, and
  • Part B: LAER/BACT Determinations for Major Polluting Facilities.
The BACT Guidelines for non-major polluting facilities include:
  • Part C: Policy and Procedures for Non-Major Polluting Facilities, and
  • Part D: BACT Guidelines for Non-Major Polluting Facilities.

For the December 2016 amendment to the Guidelines, additional parts were added to address Prevention of Significant Deterioration (PSD) requirements for greenhouse gas (GHG) emissions established by U.S. EPA in 40 CFR 52.21 in 2011. The requirements are incorporated by reference in SCAQMD Rule 1714.

The BACT Guidelines for GHG requirements include:
  • Part E: Policy and Procedures for Facilities Subject to Prevention of Significant Deterioration for Greenhouse Gases; and
  • Part F: BACT Determinations for Facilities Subject to Prevention of Significant Deterioration for Greenhouse Gases.

    The BACT Guidelines explain what BACT is, why it is required, and how it is determined for both major and non-major polluting sources. In addition, Part B of the guidelines provides detailed information on technologies contained in permits issued by SCAQMD and in permits or guidelines issued by other agencies, as well as other technologies not yet been qualified as BACT/LAER. Part D details BACT requirements for more than 100 different categories of equipment.


    SCAQMD permitting staff will determine BACT for any new, modified or relocated source at a major polluting facility on a case-by-case basis that results in the most stringent control technology or emission limit that is (1) achieved-in-practice, (2) contained in a State Implementation Plan (SIP) approved by U.S. EPA, or (3) technologically feasible and cost effective. This determination will be in accordance with Part A of the BACT Guidelines, and will consider information from Part B of the current BACT Guidelines and any other relevant information available to SCAQMD.


    For non-major polluting facilities, BACT will be based on the requirements in the MSBACT Guidelines (Part D) that were in effect at the time the application was deemed complete. Exceptions may be made based on special permitting considerations discussed in Part C of the BACT Guidelines.

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