National Emission Standards for Hazardous Air Pollutants for Source Categories

This interpretative rule clarifies the construction by EPA of the applicability of sections 112(g) and 112(j) of the Clean Air Act (CAA), and of the regulations implementing these provisions for stationary combustion turbines in Subpart B--Requirements for Control Technology Determinations for Major Sources in Accordance With Clean Air Act Sections 112(g) and 112(j). Specifically, EPA has determined that case-by-case maximum achievable control technology (MACT) determinations under subpart B must be made for all new or reconstructed major source stationary combustion turbines, regardless of whether they are part of a combined cycle system. Waste heat recovery units, including duct burners, which are part of a combined cycle system are considered to be steam generating units. New or reconstructed waste heat recovery units would not be subject to case-by-case MACT determinations under subpart B if they are electric utility steam generating units. Elsewhere in today's Federal Register, EPA is withdrawing the interpretative rule as published on April 21, 2000, at 65 FR 21636. This final interpretative rule supersedes the interpretative rule erroneously published at 65 FR 21636.