104 STAT. 2546 PUBLIC LAW 101-549—NOV. 15, 1990 "(3) PROCEDURES FOR MODIFICATIONS. — The Administrator (or the State) shall establish reasonable procedures for assuring that the requirements applying to modifications under this section are reflected in the permit. " (h) WORK PRACTICE STANDARDS AND OTHER REQUIREMENTS. — "(1) IN GENERAL.—For purposes of this section, if it is not feasible in the judgment of the Administrator to prescribe or enforce an emission standard for control of a hazardous air pollutant or pollutants, the Administrator may, in lieu thereof, promulgate a design, equipment, work practice, or operational standard, or combination thereof, which in the Administrator's judgment is consistent with the provisions of subsection (d) or (f). In the event the Administrator promulgates a design or equipment standard under this subsection, the Administrator shall include as part of such standard such requirements as will assure the proper operation and maintenance of any such element of design or equipment. "(2) DEFINITION.— For the purpose of this subsection, the phrase 'not feasible to prescribe or enforce an emission standard' means any situation in which the Administrator determines that— "(A) a hazardous air pollutant or pollutants cannot be emitted through a conveyance designed and constructed to emit or capture such pollutant, or that any requirement for, or use of, such a conveyance would be inconsistent with any Federal, State or local law, or "(B) the application of measurement methodology to a
particular class of sources is not practicable due to technological and economic limitations. "(3) ALTERNATIVE STANDARD.— I f after notice and opportunity for comment, the owner or operator of any source establishes to the satisfaction of the Administrator that an alternative means of emission limitation will achieve a reduction in emissions of any air pollutant at least equivalent to the reduction in emissions of such pollutant achieved under the requirements of paragraph (1), the Administrator shall permit the use of such alternative by the source for purposes of compliance with this section with respect to such pollutant. "(4) NUMERICAL STANDARD REQUIRED. —Any standard promulgated under paragraph (1) shall be promulgated in terms of an emission standard whenever it is feasible to promulgate and enforce a standard in such terms. "(i) SCHEDULE FOR COMPLIANCE.— "(1) PRECONSTRUCTION AND OPERATING REQUIREMENTS. —After the effective date of any emission standard, limitation, or regulation under subsection (d), (f) or (h), no person may construct any new major source or reconstruct any existing major source subject to such emission standard, regulation or limitation unless the Administrator (or a State with a permit program approved under title V) determines that such source, if properly constructed, reconstructed and operated, will comply with the standard, regulation or limitation. "(2) SPECIAL RULE.— Notwithstanding the requirements of paragraph (1), a new source which commences construction or reconstruction after a standard, limitation or regulation applicable to such source is proposed and before such standard, limitation or regulation is promulgated shall not be required to
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