Opinion ID: 6498785
Heading Depth: 3
Heading Rank: 2

Heading: NPL Listing

Text: Following the ESI, the EPA issued a proposed rule listing the Site as a groundwater plume contaminating multiple aquifers. See National Priorities List, 84 Fed. Reg. 60,357, 60,358 (Nov. 8, 2019), reprinted in J.A. 7-13. To explain its HRS analysis, the EPA provided a lengthy HRS Documentation Record, in which the EPA defined the groundwater plume “by documented observed releases [of CVOCs] in groundwater monitoring and municipal water wells in Edina and St. Louis Park.” Revised Documentation Record © Due to treatment systems set up by city and state authorities after discovering the CVOCs, “drinking water provided by both the cities of Edina and St. Louis Park currently [is] in compliance with...the Safe Drnking Water Act.” Narrative Summary, Highway 100 and County Road 3 Groundwater Plume (Nov. 2019), reprinted in J.A. 14. 13 at 13. The wells with observed releases thus defined the amorphous boundaries of the plume.’ The EPA explained that the observed releases “cannot reasonably be attributed to one or more specific sources” because of “the comingled [sic.] nature of the releases” from multiple sources, “including dry cleaners, print shops, metals fabricators,...heat treating operations, [and] other commercial and industrial facilities.” Id. at 19. The EPA then scored the Site as a “groundwater plume with no identified source.” Jd. at 20. The EPA evaluated the Site using the standard three factors. See id. at 3 (likelihood of release, waste characteristics and targets). For the likelihood of release factor, the EPA relied on groundwater samples from release and background wells in all four aquifers to establish observed releases of CVOCs through chemical analysis. See id. at 33-54. The EPA then concluded that the aquifers were interconnected based on (1) pump tests of wells showing “no significant difference in hydraulic conductivity” across all aquifers, (2) well log data from “municipal wells indicat[ing] the same stratigraphic units” and (3) “groundwater contamination ...in St. Louis Park and Edina municipal wells, as well as monitoring wells that withdraw water from” all the aquifers. /d. at 55. Given the interconnectivity and observed, not potential, releases, the likelihood of release factor for the interconnected aquifers received the maximum score. See id. After calculating the scores for waste characteristics and targets, the EPA calculated a site score of 50, id. at 2-3, well above the 28.5 threshold for NPL designation. The petitioners submitted extensive comments on the HRS analysis, primarily challenging aquifer interconnectivity. See ’ For a map of the relevant wells, see attached Appendix A, which can be found at Revised Documentation Record at 6. 14 generally J.A. 17—295. First, they took particular issue with the EPA’s purported use of a “natural migration pathway” between the Drift Aquifer and the Prairie du Chien-Jordan Aquifer. J.A. 24. Drawing on the placement of the wells used to define the plume, they argued that the EPA’s asserted pathway was scientifically impossible because it required assuming that CVOCs migrated upgradient—against the general, eastsoutheast flow of the groundwater. J.A. 266-67. Next, they contended that the EPA omitted evidence of a confining layer, the St. Peter confining layer, that would prevent permeation to the Prairie du Chien-Jordan Aquifer. J.A. 266-67, 269. In a final interconnectivity challenge, they argued that the pump tests were inadequate because they covered only the Prairie du Chien-Jordan Aquifer. J.A. 268-69.° The EPA responded at length to the petitioners’ comments. See Support Document for the Revised National Priorities List Final Rule, Highway 100 and County Road 3 Groundwater Plume (Sept. 2020) (Support Document), reprinted in J.A. 398-545. Acknowledging the interconnectivity challenges and standing by its interconnectivity findings, the EPA “identified  The petitioners also made two other challenges of note. Again assuming that the EPA had to show attribution through a “plausible migration pathway,” J.A. 266, and maintaining that the EPA had identified a “source area,” J.A. 265, they asserted that the EPA erred by ignoring possible migration pathways and sources of the CVOCs in the Prairie du Chien-Jordan Aquifer, including the Reilly Tar Site and multi-aquifer wells, J.A. 270, 275. As the name suggests, multiaquifer wells are wells that go deep enough to intersect multiple aquifers, thus providing possible paths for contaminants to migrate between aquifers. See Support Document for the Revised National Priorities List Final Rule, Highway 100 and County Road 3 Groundwater Plume, at 52 (Sept. 2020) (Support Document). In addition, they argued that the EPA improperly excluded certain documents from the administrative record. J.A. 279-80. 15 multiple lines of evidence documenting aquifer interconnections.” Jd. at 48. Responding to the natural migration pathway argument, the EPA noted that “the mechanism of vertical migration does not have to be defined” because it had documented observed releases in both the shallower aquifers and the Prairie du Chien-Jordan Aquifer. Jd. at 48, 50. It explained that it did “not identify specific migration paths through the aquifer layers as [the petitioners] suggest[;] rather,...the EPA evaluated each aquifer layer and all plausible mechanisms and evidence (natural migration in some aquifers, joints, fractures, solution channels, multi-aquifer wells, and observed contamination migration) to determine that the aquifers are interconnected for HRS purposes.” /d. at 50. Next, the EPA noted that, although it had inadvertently excluded a portion of a confining layer from one of the figures demonstrating interconnectivity, there were no continuously present confining layers because the St. Peter confining layer “is locally absent due to erosion.” /d. at 45. It also noted that the St. Peter confining layer is “[a]bsent in well HS-1 about 1.55 miles east of municipal well SLP4.” Jd. at 46. Accordingly, the EPA asserted there were no aquifer discontinuities at the site. Jd. at 49. It responded to the pump test challenge by disclaiming reliance on the pump test data to show interconnectivity. /d. at 51. In response to the petitioners’ arguments involving allegedly ignored possible sources, the EPA iterated that consistent with the classification of the Site as a groundwater plume with no identified source, it need not and did not “attribute the release to a specific source or sources.” /d. at 83. It then affirmed its definition of the Site as consistent with the HRS procedures, which permit the plume to be defined by observed releases from wells. /d. at 88. It emphasized that 16 [t]he HRS is a screening model that uses limited resources to determine whether a site should be placed on the NPL for possible Superfund response. AS necessary, additional investigations to determine definitive sources at a particular site are performed at the [Remedial Investigation/Feasibility Study] stage of the Superfund process at which time site conditions and hazards are characterized more comprehensively. Id. at 87. The EPA also iterated that “the fact that [it] initially identifies and lists the [site] based on areview of contamination at a certain location—in this case a contaminated groundwater plume with no identified source—does not necessarily mean that the site boundaries are limited to that location.” /d. at 11. In response to the petitioners’ contention that it had ignored multi-aquifer wells as a contributor to contaminant migration, the EPA pointed out that multi-aquifer wells do “influence ... contaminant migration” and therefore “[t]he presence of multi-aquifer wells at this Site only provides additional documentation of hydrological interconnections between the aquifer layers at the Site.” Jd. at 52. Replying to the petitioners’ claim that it had improperly excluded from the administrative record adverse evidence provided by them, the EPA acknowledged that it “must include all pertinent information in the administrative record, both favorable and unfavorable to [its] final decision.” /d. at 14. It then stated it had “included all the relevant information it considered to support the HRS score in this case and all such information has been placed in the listing docket that makes up the administrative record.” /d. It also noted that the petitioners “ha[d] not explained how the submitted documents impact the HRS score.” Id. 17 The EPA issued the final rule adding the Site to the NPL on September 3, 2020. Site Listing Rule, 85 Fed. Reg. at 54,933. The petitioners filed a timely petition for review. On May 4, 2021, they filed a Motion for the Court to Review and Consider Extra-Record Evidence. Under CERCLA, we have jurisdiction to review the petition. See 42 U.S.C. § 9613(a). Il. ANALYSIS Echoing their comments to the agency, the petitioners mount two challenges to the NPL listing. We begin with their claim that the EPA arbitrarily and capriciously defined the site by ignoring possible sources of contamination. We then address their substantial-evidence and arbitrary-and-capricious aquifer interconnectivity challenges. Because the EPA properly followed the HRS scoring procedures, supported its conclusions with substantial evidence and adequately addressed the petitioners’ comments, we conclude that their claims are without merit. Finally, we deny their motion to supplement the record with extra-record evidence. A. STANDARD OF REVIEW We review the EPA’s NPL listing decisions under the Administrative Procedure Act’s (APA) arbitrary and capricious and substantial evidence standards. See Genuine Parts, 890 F.3d at 311 (citations omitted). Given “the ‘highly technical issues involved’ [in an NPL listing] and because the NPL serves merely as a ‘rough list of priorities, assembled quickly and inexpensively,’” we afford the EPA “significant deference” in NPL listing decisions. Carus Chem., 395 F.3d at 441 (quoting Bradley Mining Co. v. EPA, 972 F.2d 1356, 1359 (D.C. Cir. 1992)). 18 If an agency has “entirely failed to consider an important aspect of the problem [or] offered an explanation for its decision that runs counter to the evidence before the agency,” Motor Vehicle Mfrs. Ass’n of U.S., Inc. v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29, 43 (1983), we will vacate its decision as arbitrary and capricious. We will, however, “uphold a decision of less than ideal clarity if the agency’s path may reasonably be discerned.” Bowman Transp., Inc. v. Arkansas-Best Freight Sys., Inc., 419 U.S. 281, 286 (1974). Substantial evidence review requires that we “consider the whole record upon which an agency’s factual findings are based,” Genuine Parts, 890 F.3d at 312, to determine if the agency “ignore[d] evidence contradicting its position,” Butte County v. Hogen, 613 F.3d 190, 194 (D.C. Cir. 2010), or “minimize[d] such evidence without adequate explanation,” Genuine Parts, 890 F.3d at 312 (citation omitted). “[I]n their application to the requirement of factual support[,] the substantial evidence test and the arbitrary or capricious test are one and the same.” Butte County, 613 F.3d at 194 (citation omitted). B. SITE DEFINITION CHALLENGES We first address the petitioners’ claim that the “EPA arbitrarily included the Drift Aquifer Area in the Site definition while ignoring relevant evidence of other known areas of contamination.” Pet’rs Br. 59. As a preliminary matter, the petitioners coin the term “Drift Aquifer Area” and employ it to refer to a triangular area surrounding the three release wells in the Drift Aquifer.’ See id. at 6-8. They contend that the EPA ’ For a depiction of the general area of the petitioners’ Drift Aquifer Area, see Appendix B, which is available at Petitioners Brief 8. This map also includes the layout of the release wells but 19 did not “holistically evaluate[]” the Site and should “eliminate the arbitrarily exclusive Drift Aquifer Area from the Site definition.” /d. at 12. The Site definition is arbitrarily exclusive, they argue, because even after determining the aquifers were interconnected, the EPA “failed to include additional, contaminated Drift [Aquifer] wells or locations in the Site definition.” Jd. at 60. They point out that their comments directed the EPA toward a number of possible sources of the contaminants—including the Reilly Tar Site, other industrial facilities and multi-aquifer wells—but that the EPA nevertheless arbitrarily excluded these other contaminated areas from the Drift Aquifer Area. See id. at 5963. The petitioners are mistaken for three reasons. First, and most fundamentally, the EPA did not arbitrarily exclude any sources because it properly defined the Site as a groundwater plume with no identified source. See Revised Documentation Record at 20; see also HRS 8§ 1.1, 3.1.1. Pursuant to the HRS procedures, see supra, at 6-8, the EPA defined the site by using chemical analysis to show that observed releases had occurred across the four aquifers. Revised Documentation Record at 33— 53. Then, after considering “several likely sources and/or potential contributors,” the EPA reasonably determined that because of the “comingled [sic.] nature of the releases” likely resulting from one or more sources, it could not attribute the observed releases to a specific source.!° Id. at 19; see also id. at 54-55; Support Document at 26, 84. was created for this litigation and may not depict precise boundaries of the groundwater plume. 10 As the petitioners note, the HRS Manual states that “efforts should be undertaken to identify the original source(s) of contamination” prior to scoring a site as a groundwater plume 20 Second, to define a site under the HRS procedures, the EPA need not “evaluate all known releases,” Pet’rs Br. 12, or “include additional, contaminated Drift [Aquifer] wells,” id. at 60. The petitioners point to no HRS requirement that the EPA must sample every well with a potential release. Such a requirement would be inconsistent with the “narrowly focused” purpose of the NPL and the HRS: “identify[ing], quickly and inexpensively, sites that may warrant further action under CERCLA.” Eagle-Picher Indus., Inc. v. EPA (Eagle-Picher 1), 759 F.2d 905, 911 (D.C. Cir. 1985). Listing does not set the Site boundaries in stone. As more information becomes available in the remedial investigation/feasibility study stage, the EPA may expand (or contract) the Site. See Revised Documentation Record at 1; Wash. State Dep ’t of Transp., 917 F.2d at 1310 n.1. Third, the EPA did not arbitrarily ignore the petitioners’ comments on other plausible sources of contamination, including the Reilly Tar Site and multi-aquifer wells.'! Indeed, the EPA acknowledged their comments regarding the possibility that other sources may contribute to contamination, without an identifiable source. HRS Manual, supra, at 46. But those efforts need only be “equivalent to those of an expanded [site inspection].” Jd. The EPA met that standard by relying on the MPCA’s Expanded Site Inspection Report, which documented the latter’s efforts to identify a single source of the groundwater contamination. See Revised Documentation Record at 13-14. ‘| The petitioners assert that other possible sources are: a previous Schloff Chemical release of PCE, a former Flame Metals facility, a former Control Data Corporation site, a Lindberg Heat Treating Facility, a former Reynolds Welding site, Pet’rs Br. 60-62; see also J.A. 274—76, and “the area near the intersection of Highway 7 and Louisiana Avenue,” Pet’rs Br. 42 (quoting J.A. 387). See also id. at 66 (map of petitioners’ asserted possible sources). 21 Support Document at 27, 31-33, and noted that “additional characterization is necessary to delineate the plume and attribute the release to a facility,” id. at 31. “Moreover,” the EPA explained, CVOC contamination associated with other facilities like the Reilly Tar Site “supports the evaluation of the site as a contaminated groundwater plume without an identified source because the significant increase in the plume could not be attributed to a specific source.” Id. (emphasis added). The EPA also acknowledged and even agreed that contamination can migrate through multi-aquifer wells.'? Jd. at 51-52.