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

Heading: Demonstrations Supporting Stack Height Increases Within the Formula.

Text: 66 1. Attacks on the formula. In the Sierra Club litigation the environmental petitioners did not directly challenge the accuracy of the stack height formula. (By then the 2.5H formula had evolved into H + 1.5L, where L refers to the lesser of the height or width of any structure near the stack. Some references are to formulas in the plural because the old 2.5H persisted as to some grandfathered stacks.) They did, however, attack the agency's failure to require demonstrations to justify stack height credit in either of two special cases: (1) when a source raised a preexisting stack, and (2) when federal, state or local authorities believed the formula had overstated the necessary stack height. The EPA in turn defended the omission of such demonstration requirements largely on the ground of the formula's accuracy. 719 F.2d at 456. The court found this faith unsupported by the record, as it was explicitly based on the agency's erroneous relativistic conception of excessive concentrations. 12 Id. at 458. The court therefore held that the agency had not considered whether the formulas were an accurate enough measure, in light of the construction of excessive concentrations as related to health and welfare, to justify dispensing with a demonstration requirement in the two special cases. It remanded for that reconsideration. Id. Thus, despite the absence of direct attack, the Sierra Club decision invited reconsideration of the formula, by suggesting to EPA that superior validation of the formula was an alternative to adopting demonstration requirements in the areas specifically found to be vulnerable. 67 On remand, the agency provided demonstration requirements not only for the two circumstances specifically disputed in the preceding litigation, 40 C.F.R. Secs. 51.1(kk)(2) (stack height increase demonstration), 51.1(kk)(3) (governmental authority instigated demonstration), but also for sources with porous structures or buildings whose shapes are aerodynamically smoother than the simple structures on which the formulae were based. 50 Fed.Reg. 27,900/2 (explaining the reach of 40 C.F.R. Sec. 51.1(kk)(3)). Given these demonstration requirements, nothing in our Sierra Club opinion required EPA to reevaluate the accuracy of its formula. Accordingly, consideration of deficiencies in the formula is barred by res judicata (and by the time limits of 42 U.S.C. Sec. 7607(b)(1)), unless we find that the demonstration procedures chosen by EPA are insufficient to fulfill the statutory purposes. We now turn to that issue. 68 2. Attacks on the demonstration procedures. In Sierra Club this court found it proper to assume that large plants of the sort at issue here would have been built in accordance with good air quality management practices, or, effectively, GEP as the term is used in Sec. 123. 719 F.2d at 459. The corollary of this was an assumption that post-construction stack increases were not justified by any need to correct downwash-induced dangers to health and welfare. The court said that this assumption could be rebutted in individual cases only by a reliable indicator of the height needed for that purpose. Id. 69 EPA responded by imposing demonstration requirements. Under the 1985 regulations, sources seeking credit for height increases must show, through fluid modeling or wind tunnel demonstrations, that the increase is necessary to avoid downwash that would otherwise exceed at least one of several health- or welfare-related criteria (applicable NAAQS, prevention of significant deterioration standards covering areas in full attainment of the NAAQS under Sec. 7475(a)(4), or levels amounting to a local nuisance). 40 C.F.R. Sec. 51.1(kk)(2). As noted above, a source is to assume for the purposes of the demonstration an emission level equivalent to the applicable SIP, or, if no SIP applies, to its actual emissions rate. Id. 70 NRDC argues that these emissions rate assumptions undermine the demonstrations, denying them the reliability demanded by Sierra Club. As we have noted, an assumption of existing or SIP-required emissions rates plainly gives the demonstrations a certain circularity: the now existing or required emissions rate will have been based on a given stack height, which will then be used to justify a stack height. NRDC Brief at 29. 13 NRDC argues that instead EPA was required to assume the best achievable emissions rate. Id. at 22. 71 We have already rejected NRDC's claims that failure to employ control-first assumptions directly violates Sec. 123 or is arbitrary and capricious in light of EPA's own condemnation of circularity and partial adoption of control-first for above-formula demonstrations. The sole question currently before us, then, is whether EPA's use of existing rates in this context is so defective as to fall short of Sierra Club 's reliability requirement. 72 We note at this point that the agency's failure to establish perfect logic in support of its emissions baseline decision may well stem from the nature of Sec. 123 itself. While its goal is the reduction of overall pollution loadings, at least in part with a view to protect against acid rain in regions distant from the sources, it operates solely on the means by which sources meet national goals for local health and welfare. It would be startling if implementation of this process did not involve a few logical imperfections. 73 There appears, in fact, to be no completely logical basis on which to select a baseline rate for any demonstration. If EPA were to use NSPS for all demonstrations, for example, demonstrations would in a sense underpredict the appropriate stack height for sources with higher emissions rates. Assumption of a single high emissions rate, conversely, would overpredict the appropriate stack height for cleaner plants. But selecting each plant's existing permitted rate is subject to the circularity objection. In this world of imperfections, we think EPA's choice reasonable. This is particularly so in light of Congress's having obviously contemplated reliance on a historic notion of good engineering practice, a notion developed during an era of relatively primitive emissions controls. We do not find EPA's methodology for the conduct of within-formula demonstrations arbitrary or capricious. 74