104 STAT. 2548 PUBLIC LAW 101-549—NOV. 15, 1990 subparagraph as a condition of granting the extension authorized by the previous sentence. "(B) An existing source which achieves the reduction referred to in subparagraph (A) after the proposal of an applicable standard but before January 1, 1994, may qualify under subparagraph (A), if the source makes an enforceable commitment to achieve such reduction before the proposal of the standard. Such commitment shall be enforceable to the same extent as a regulation under this section. "(C) The reduction shall be determined with respect to verifiable and actual emissions in a base year not earlier than calendar year 1987, provided that, there is no evidence that emissions in the base year are artificially or substantially greater than emissions in other years prior to implementation of emissions reduction measures. The Administrator may allow a source to use a baseline year of 1985 or 1986 provided that the source can demonstrate to the satisfaction of the Administrator that emissions data for the source reflects verifiable data based on information for such source, received by the Administrator prior to the enactment of the Clean Air Act Amendments of 1990, pursuant to an information request issued under section 114. "(D) For each source granted an alternative emission limitation under this paragraph there shall be established by a permit issued pursuant to title V an enforceable emission limitation for hazardous air pollutants reflecting the reduction which qualifies the source for an alternative emission limitation under this paragraph. An alternative emission limitation under this paragraph shall not be available with respect to standards or requirements promulgated pursuant to subsection (f) and the Administrator shall, for the purpose of determining whether a standard under subsection (f) is necessary, review emissions from sources granted an alternative emission limitation under this paragraph at the same time that other sources in the category or subcategory are reviewed. "(E) With respect to pollutants for which high risks of adverse public health effects may be associated with exposure to small quantities including, but not limited to, chlorinated dioxins and furans, the Administrator shall by regulation limit the use of offsetting reductions in emissions of other hazardous air pollutants from the source as counting toward the 90 per centum reduction in such highrisk pollutants qualifying for an alternative emissions limitation under this paragraph. "(6) OTHER REDUCTIONS.—Notwithstanding the requirements of this section, no existing source that has installed— "(A) best available control technology (as defined in section 169(3)), or "(B) technology required to meet a lowest achievable emission rate (as defined in section 171), prior to the promulgation of a standard under this section applicable to such source and the same pollutant (or stream of pollutants) controlled pursuant to an action described in / subparagraph (A) or (B) shall be required to comply with such standard under this section until the date 5 years after the date
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