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The Texas Commission on Environmental Quality (TCEQ) recently issued a memo on the vacaturs of several Maximum Achievable Control Technology (MACT) standards by the United States Court of Appeals for the District of Columbia Circuit (the D.C. Court). Because the EPA fails to promulgate the MACT standards by the dates established in the federal Clean Air Act (CAA), the TCEQ must provide case-by-case MACT for major sources of hazardous air pollutants (HAP) under CAA, §§ 112(g) and 112(j). Under CAA §112(g), states must impose MACT standards on a case-by-case basis for construction of a new major source or modification of an existing major source in a source category that has no national MACT standards. Under CAA §112(j) (a.k.a. "MACT Hammer"), when EPA fails to promulgate a standard for a source category, the Title V permits for such sources shall contain emission limitations determined by states on a case-by-case basis that are equivalent to the MACT that EPA should have established.

The rules affect Title V sources that currently have permit conditions citing the vacated rules listed in the table below. The EPA has not issued guidance and the federal court has not clarified these requirements as of the date of this writing. Before receiving any EPA guidance or federal clarification on the requirements, sources can review their potential applicability and options under CAA, §§ 112(g) and (j).

Adapted from the TCEQ, Interoffice Memorandum, "Compliance Reviews of Maximum Achievable Control Technology (MACT) recently vacated by the Federal Courts", November 10, 2008.

MACT Category (Subpart)

Effective Date

Number of sites subject to the vacated MACT

Brick (JJJJJ) -National Emissions Standards for Hazardous Air Pollutants (NESHAP) for Brick and Structural Clay Products Manufacturing


Full Vacatur


Clay Ceramics (KKKKK) - NESHAP for Clay Ceramics Manufacturing


Full Vacatur


Boiler (DDDDD) - NESHAP for Boilers and Process Heaters


Full Vacatur


Clean Air Mercury Rule (CAMR)