Opinion ID: 187435
Heading Depth: 2
Heading Rank: 3

Heading: Carbon Error

Text: In making nonattainment designations, EPA relied upon a mistaken estimate of carbon emissions by power plants that burn bituminous coal. Industry petitioners seize on this error as evidence that the Designations Rule is arbitrary and capricious. We disagree. EPA used the best available information, and the mistaken estimate of carbon had no effect on the reasonableness of the challenged designations. Among the analytical tools EPA uses to make designation determinations is a county's weighted emissions score, which allows the agency to compare SO2, NOx, carbon, and crustal emissions across counties within a C/MSA. See PM 2.5 Designations Rule, 70 Fed.Reg. at 947. This score is not based on measurements of actual emissions by a particular source. Instead, EPA uses emissions estimates from the National Emissions Inventory (NEI) to calculate total PM2.5 emissions, as well as SO2, NOx, carbon, and crustal emissions for each county. See What Is the National Emissions Inventory (NEI)?, http://www. epa.gov/ttn/chief/net/neiwhatis.html (last visited June 11, 2009). The NEI is a database assembled by EPA's Emission Inventory and Analysis Group that houses estimates of the kinds and amounts of substances emitted by particular sources, including point sources like power plants and mobile sources like automobiles. Based on these estimates, EPA creates speciation profiles, which describe the chemicals that make up the emissions associated with a particular type of source. See Speciation: Emissions Modeling Clearinghouse, http://www.epa.gov/ttn/ chief/emch/speciation/ (last visited June 11, 2009). The speciation profile EPA used for large electric generating units (EGUs) estimated that carbon makes up 21% of their PM2.5 emissions. As it turns out, that estimate was wrong for plants that burn bituminous coal. Carbon accounts for only 2.9% of their PM2.5 emissions. See J.A. at 2848-49. EPA updated the speciation profile for these plants in its 2006 revision of the PM2.5 NAAQS, but retained the old profile for plants that burn primarily lignite coal. Industry petitioners argue that because the 2004 designations were based on a flawed EGU profile that vastly overestimated carbon emissions, EPA's nonattainment designations for counties with large electric power plants that burn bituminous coal  particularly the 23 identified in the petition for reconsideration  are likewise flawed. EPA responds that its ultimate designations did not turn on any one estimate of a single chemical component of PM2.5. Rather, the agency relied on numerous data points, including emissions levels and county rankings of weighted emissions scores within a C/MSA, that were largely unaffected by the lower carbon estimate. According to EPA, changes in the speciation profile for plants that burn bituminous coal did not substantially lower total PM2.5 emissions estimates. Instead, the proportions of pollutants emitted by these sources changed. Specifically, the estimate of crustal particles, also a precursor to PM2.5, increased as the carbon estimate decreased. See Johnson Attach. at 4. We hold that EPA was not obligated to upend the designations process when it discovered a mistake in its speciation profile for certain power plants. EPA used the best information available in making its designations, and that is all our precedent requires. In American Iron & Steel Institute v. EPA, 115 F.3d 979, 1006 (D.C.Cir.1991), the petitioners argued that EPA's estimate for the mercury concentration permitted in the Great Lakes was flawed because the agency used inaccurate data that had since been corrected. Relying on ICC v. Jersey City, 322 U.S. 503, 64 S.Ct. 1129, 88 L.Ed. 1420 (1944), and Vermont Yankee Nuclear Power Corp. v. Natural Resources Defense Council, 435 U.S. 519, 98 S.Ct. 1197, 55 L.Ed.2d 460 (1978), we held that EPA did not act arbitrarily by using the older data in its calculation. The agency was not obliged to stop the entire process because a new piece of evidence emerged. If this were true then the administrative process could never be completed. An agency does, however, have an obligation to deal with newly acquired evidence in some reasonable fashion. Am. Iron, 115 F.3d at 1007. Here, EPA dealt with newly acquired evidence in a reasonable fashion by explaining why it would not have changed the challenged designations. EPA is correct that revisions to the speciation profile for plants that burn bituminous coal altered only one component of the weighted emissions score, which itself is only one of numerous analytical tools used to assess the first of nine factors EPA considers in determining contribution to PM2.5 violations. Speciation profiles for power plants are by no means the exclusive or even the primary basis for EPA's designations, but merely make up one part of a much larger and multi-factored decisionmaking process. Johnson Attach. at 6-7. Petitioners nonetheless contend that the carbon error is particularly important because carbon typically makes up a large portion of the urban excess and therefore weighs heavily in these counties' weighted emissions scores, which themselves weigh heavily in the contribution analysis because of the presence of large power plants. That may be so, but EPA granted a March 2006 request to recalculate the weighted emissions scores using the revised estimates and concluded that even if [the agency] were to reconsider the designations, the area by area evaluation of counties with emissions scores or activities contributing to violations of the NAAQS would not result in a different outcome. Of the counties [petitioners] identified in [their] petition, EPA sees no change in the rank or magnitude of sources relative to other counties in the areas that would negate the appropriateness of inclusion of the counties within their respective designated nonattainment areas. Letter from Stephen L. Johnson, Adm'r, EPA, to David M. Flannery, Counsel For Midwest Ozone Group et al. 2-3 (Aug. 16, 2007); see also J.A. at 2881-83 (showing initial and revised scores for the 23 counties identified by petitioners); Johnson Attach. at 10-12 (explaining why particular designations would not have changed with new data). Even with a change in the estimated proportion of carbon emitted by plants that burn bituminous coal, the overall level of pollutants emitted by those EGUs generally stayed the same, as did county rankings of weighted emissions scores. For example, EPA explained that using the new speciation data for a power plant in Jefferson County, Indiana, would not have changed its nonattainment designation despite industry petitioners' claim that it is among the most problematic of EPA's determinations. See J.A. at 2826 (Midwest Ozone Petition for Reconsideration). Although the weighted emissions score for Jefferson County would have been lower, it still would have been higher than surrounding counties' scores because of the significant levels of SO2 and NOx that the county's power plant continued to emit. Johnson Attach. at 12. EPA dealt with the so-called carbon error in a reasonable fashion.