Opinion ID: 501652
Heading Depth: 2
Heading Rank: 3

Heading: EPA's Definition of Stack Height in Existence

Text: 121 In Sierra Club petitioners contended that EPA's definition of stack in existence on December 31, 1970, as used in Sec. 123(a), impermissibly extended protection to stacks merely under construction. The court accepted EPA's view. 719 F.2d at 464-65. At the time, the record before the court indicated that only four to eight plants would be affected by the dispute, and the court mentioned this fact. Id. at 465. NRDC now contends that the broader definition will encompass 32-to-98 utility sources, NRDC Brief at 74, and challenges EPA's refusal to reconsider the issue in light of this reassessment of its probable impact. 122 Although the Sierra Club court indisputably mentioned the limited number of plants thought to be affected, its acceptance of EPA's interpretation rested on the view that it was necessary to make the clause equitable, which was undoubtedly Congress's purpose, 719 F.2d at 465, not on the number of plants affected. We recognize that under the balancing test by which retroactivity is evaluated, frustration of the statutory purpose is a key element militating against non-retroactive application. The new discoveries of affected plants up the ante. But the in existence definition did not represent a de novo retroactivity decision by EPA, merely an implementation of Congress's decision. NRDC points us to nothing in the prior rulemaking suggesting that the number of plants affected influenced EPA's choice of the broader definition. Compare 46 Fed.Reg. at 49,816/1 (Oct. 7, 1981) (expressing decision to broaden definition without a word as to the number of plants). Accordingly, we are not confronted with a case where a significant factual predicate of a prior decision has been removed, which may sometimes trigger a duty to revisit the issue. See WWHT, Inc. v. FCC, 656 F.2d 807, 819 (D.C.Cir.1981); Geller v. FCC, 610 F.2d 973, 980 n. 59 (D.C.Cir.1979). EPA's adherence to its prior position is lawful. We would be reluctant in any event to start undermining a six-year-old provision governing the scope of Congress's 10-year-old choice to protect decisions actually made more than 17 years ago. 123