Opinion ID: 796659
Heading Depth: 3
Heading Rank: 3

Heading: Zero Entrainment Survival Assumption

Text: 125 The Phase II Rule requires a reduction of impingement mortality, but a reduction of entrainment generally. See 40 C.F.R. § 125.94(b). The industry petitioners contend that the EPA improperly presumed that all entrained organisms are killed. They argue that the Rule's assumption that no organisms survive entrainment is contrary to the evidence which, in their view, indicates a survival rate of significantly more than zero. We conclude that in light of uncertain record evidence, the EPA acted within its discretion in assuming zero entrainment survival. 126 The EPA explained in the preamble to the Phase II Rule that it assumed zero percent entrainment survival because it does not have sufficient data to establish performance standards based on entrainment survival for the technologies used as the basis for today's rule. 69 Fed.Reg. at 41,620. It explained further that it believes the current state of knowledge does not support reliable predictions of entrainment survival that would provide a defensible estimate for entrainment survival above zero at a national level. Id. It also stated that the performance standard would likely have been higher had it incorporated entrainment survival into its conclusions. Id. While impingement mortality can be readily quantified, the EPA contends, entrainment mortality cannot because many entrained organisms are small, fragile, and prone to disintegrate during entrainment. The EPA also contends that death from entrainment sometimes occurs immediately but other times only after an organism is discharged back into the waterbody. In view of these factors, the EPA claims that it reasonably concluded that the available data did not support an estimate of entrainment survival at the national level. 127 None of the peer reviewers accepted the EPA's assumption of zero percent survival. For instance, peer reviewer Dr. Mark Bain was not convinced by the arguments presented that fish do not survive entrainment in significant numbers and concluded that there is very strong evidence that entrainment survival is not zero. Another peer reviewer, Dr. Charles Hocutt, concluded that the EPA's assumption is based on inference and innuendo and does not statistically refute opposing views. Although peer reviewer Dr. Greg Garman stated that the study submitted by the power industry was very clearly biased and too seriously flawed to provide a serious challenge to the EPA position, he also noted that EPA's position is only slightly more defensible given the lack of rigorous statistical analyses. 128 No peer reviewer, however, expressed the belief that reliable national statistics on entrainment survival exist. Hocutt found it difficult for the layman and professional alike to draw confident conclusions without a detailed analysis of the evidence, and Garman suspected a lack of sufficient data to conduct a definitive and statistically valid test of the EPA zero survival assumption. While these comments do not, on balance, support the EPA's assumption, neither do they reflect any meaningful agreement on the incidence of entrainment survival. 129 Given the statutory directive to set national standards and the well-documented uncertainty in the entrainment data, the EPA was well within its authority to determine that it could not provide a reasonable estimate of entrainment survival on a national basis. Judicial review is considerably deferential when the agency's decision rests on an evaluation of complex scientific data within the agency's technical expertise. Texas Oil & Gas Ass'n, 161 F.3d at 934; City of Waukesha v. EPA, 320 F.3d 228, 247 (D.C.Cir.2003) (stating that an agency is entitled to an extreme degree of deference . . . when it is evaluating scientific data within its technical expertise (citation and internal quotation marks omitted)). Moreover, it is within EPA's discretion to decide that in the wake of uncertainty, it would be better to give the values a conservative bent rather than err on the other side. Am. Iron & Steel Inst. v. EPA, 115 F.3d 979, 993 (D.C.Cir.1997). Indeed, one peer reviewer expressly noted that the EPA had adopted a conservative approach by its assumption of zero entrainment survival in the Rule. It is thus clear that the EPA acted well within its discretion in presuming zero entrainment survival after the Agency had reviewed a substantial body of complex scientific data, and acknowledging that the evidence is inconclusive, it adopted a conservative approach. 130 For these reasons and those stated in Riverkeeper I, we therefore defer to the EPA's judgment of how best to define and minimize `adverse environmental impact.' 358 F.3d at 197.