42 U.S. Code § 7651f - Nitrogen oxides emission reduction program
On the date that a coal-fired utility unit becomes an affected unit pursuant to sections 7651c, 7651d, 7651h of this title, or on the date a unit subject to the provisions of section 7651c(d) or 7651h(b) of this title, must meet the SO2 reduction requirements, each such unit shall become an affected unit for purposes of this section and shall be subject to the emission limitations for nitrogen oxides set forth herein.
In lieu of complying with the applicable emission limitations under subsection (b)(1), (2), or (d), the owner or operator of two or more units subject to one or more of the applicable emission limitations set pursuant to these sections, may petition the permitting authority for alternative contemporaneous annual emission limitations for such units that ensure that (1) the actual annual emission rate in pounds of nitrogen oxides per million Btu averaged over the units in question is a rate that is less than or equal to (2) the Btu-weighted average annual emission rate for the same units if they had been operated, during the same period of time, in compliance with limitations set in accordance with the applicable emission rates set pursuant to subsections (b)(1) and (2).
If the permitting authority determines, in accordance with regulations issued by the Administrator not later than eighteen months after November 15, 1990;  that the conditions in the paragraph above can be met, the permitting authority shall issue operating permits for such units, in accordance with section 7651g of this title and part B 3 of title III, that allow alternative contemporaneous annual emission limitations. Such emission limitations shall only remain in effect while both units continue operation under the conditions specified in their respective operating permits.
 So in original. Probably should be followed by “or”.
 So in original. No par. (2) has been enacted.
 See References in Text note below.
 So in original. Probably should be “subsections,”.
 So in original. The semicolon probably should be a comma.
Part B of title III, referred to in subsecs. (d) and (e), means title III of the Clean Air Act, act July 14, 1955, ch. 360, as added, which is classified to subchapter III of this chapter, but title III does not contain parts. For provisions of the Clean Air Act relating to permits, see subchapter V (§ 7661 et seq.) of this chapter.