Supreme Court Preview: Climate Cases, RCRA, and Natural Gas

Environmental law is at the front and center of the Supreme Court’s October Term 2026 docket. Perhaps the most watched decision will be that in Suncor Energy Inc. v. County Commissioners of Boulder County, a state law climate action brought by the City and County of Boulder, Colorado against two major fossil fuel producers.[1] Depending on the Court’s ruling, municipal plaintiffs like Boulder may either be completely preempted from bringing state law climate actions against fossil fuel companies or emboldened to file similar suits. Alternatively, lingering questions regarding the Court’s jurisdiction may lead to a purely procedural decision that does not touch the weighty preemption issues. 

In addition to Suncor, the Court has agreed to decide two other environmental law cases this term. Department of the Air Force v. Prutehi Guåhan concerns the U.S. Air Force’s plan to continue disposing of munitions by detonating them on a beach in Guam and the potential interaction between the federal Resource Conservation and Recovery Act (RCRA) and the National Environmental Policy Act (NEPA).[2] The Court will also hear argument in Hoffmann v. WBI Energy Transmission, Inc., a case regarding proper compensation following the use of eminent domain power under the Natural Gas Act, with implications for where and how natural gas pipelines are built.[3]

Suncor Energy Inc. v. County Commissioners of Boulder County

Boulder’s case against Suncor Energy (a major Canadian fossil fuel producer) and ExxonMobil (the world’s largest non-state oil and gas company) hinges on state law tort claims. These claims allege that both companies knowingly caused climate-related harms through the production, sale, and marketing of their fossil fuel products, while at the same time concealing and mispresenting those same harms. First filed in 2018, Boulder’s suit survived a lengthy removal campaign before ultimately making its way before the Colorado Supreme Court in 2025 following a show cause order. There, a 5-2 majority concluded that the text of the federal Clean Air Act (CAA) did not preempt Boulder’s claims and that federal common law displaced by the CAA also did not bar the state law tort action.[4]

The Colorado Supreme Court’s decision to allow Boulder’s suit to proceed in state court prompted Suncor and Exxon to seek Supreme Court review. In their petition for certiorari and briefing, the Petitioners again argued that Boulder’s tort claims are preempted by the CAA, which they contend grants the federal government the exclusive authority to regulate interstate air pollutants like the greenhouse gases emitted from burning fossil fuels.[5] Suncor and Exxon also argued that the Constitution’s structure of equal sovereignty inherently precludes state law from addressing interstate air pollution. Under that argument, the passage of the CAA merely codified federal preemption of state regulation of interstate air pollution, meaning that Boulder’s claims would be preempted even if the CAA did not exist. 

In contrast, Boulder’s briefing to the Court contended that state law has consistently applied to harmful conduct taking place beyond state borders, imposing liability in cases involving national sales of defective products, interstate anti-trust actions, and international fraud.[6] Given that history, Boulder argued that the Constitution cannot implicitly preempt state tort actions addressing out-of-state conduct. Under Boulder’s theory of the case, the only true question at issue is whether the text of the CAA bars state law tort claims addressing injuries caused by fossil fuel production and marketing. Boulder’s follow-up argument is that the CAA’s permitting system for air pollutant sources does not implicate the upstream production and promotion of greenhouse gas-emitting fossil fuels, resulting in no preemption of the City and County’s claims against Suncor and Exxon. 

As required by the Court’s grant of certiorari, Boulder and the fossil fuel companies also briefed whether the Supreme Court has jurisdiction over the case. Boulder argued that the Court lacked jurisdiction, as the Colorado Supreme Court did not issue a reviewable final judgment but rather only declined to end litigation at the pleading stage. Suncor and ExxonMobil maintained that the Court could exercise jurisdiction because the Colorado Supreme Court’s ruling was in fact a final judgment that also deprived the Petitioners of a federal preemption defense, subjecting the companies to continued litigation costs and increased liability risk. 

Briefing on both sides, including the many amicus briefs filed by states, industry groups, U.S. Senators and others, highlighted the potential ramifications of the Court’s ruling in this case. Suncor and Exxon, along with their aligned amici, argued that if Boulder’s state law claims can survive federal preemption, hundreds if not thousands of other municipalities will file a massive and assertedly ruinous wave of similar suits against the fossil fuel industry. On the other hand, Boulder and supporting amicus briefs warned that preemption of state law claims under the CAA would seriously damage states’ regulatory powers and call into question whether plaintiffs are able to use state tort claims to address misconduct that crosses state lines. 

An eight-justice panel wrestled with the potential consequence of the case during oral argument on October 5, following Justice Alito’s recusal due to his investments in oil and gas companies. Several justices, namely Chief Justice Roberts, Justice Kagan, and Justice Kavanaugh, asked questions regarding the differences between Boulder’s suit and previous tort actions addressing nationwide harms, such as tobacco and opioid litigation, and inquired whether environmental harms merit a different preemption analysis. Justice Roberts and Justice Thomas also voiced concerns regarding the potential scope of future litigation against the fossil fuel industry if Boulder’s claims are not preempted. However, Justice Sotomayor and Justice Jackson focused questioning on the Court’s jurisdiction, raising the prospect that the Court may avoid the potentially broad consequences of a substantive ruling by finding a lack of jurisdiction. 

Suncor may become a landmark case for climate change litigation, as dozens of similar suits alleging state law tort claims have already been filed in state courts across the country. Depending on the Court’s ruling, state and municipal plaintiffs may be able to seek recovery against the fossil fuel industry without fear of federal preemption, or state law climate litigation may be largely stymied by the CAA’s preemptive power. A less significant outcome may occur, however, if the Court finds that it lacks jurisdiction and leaves a substantive decision on the significant preemption issues for a later case. 

Department of the Air Force v. Prutehi Guåhan

This case concerns the U.S. Air Force’s pending application to renew its RCRA permit allowing for munitions disposal through detonation on the Territory of Guam. Prutehi Guåhan, a Guam-based group dedicated to protecting the island’s natural and cultural resources, filed a January 2022 suit in federal district court seeking to block the permit renewal on the grounds that the Air Force failed to properly perform a NEPA review in its RCRA application. While the case was originally dismissed by the district court, the Ninth Circuit reversed the dismissal in February 2025. The Air Force then petitioned for certiorari. 

The Supreme Court granted certiorari in Prutehi Guåhan to determine two issues: (1) whether a RCRA permit renewal is a reviewable final agency action under the Administrative Procedure Act (APA) and (2) whether federal government agencies must comply with NEPA’s environmental review procedures when preparing a RCRA permit renewal application. In its briefing, the Air Force argued that its permit renewal application is not a final action, as the application does not determine a legal right or obligation until it is granted by the reviewing agency (Guam EPA).[7] The Air Force also claimed that RCRA’s own environmental review procedures designed specifically for hazardous waste supersede NEPA’s environmental review requirements.

Prutehi Guåhan’s briefing argued that the Air Force’s permit application was a decision to continue to detonate munitions and therefore constituted a final action resulting in legal consequences.[8] The group also contended that Congress’ explicit exemption of certain federal actions from NEPA does not extend to RCRA permit applications and that RCRA permit renewal does not fulfill NEPA’s hard-look review requirements. Accordingly, the Respondent claimed that RCRA did not displace the Air Force’s obligation to complete a proper review under NEPA. 

The Court heard argument in from both parties on October 7. Much of the questioning focused on the APA reviewability issue, with several justices raising concerns that the Air Force’s permit application could be a final agency action. However, the justices also appeared receptive to Prutehi Guåhan’s arguments regarding NEPA’s review requirements applying to the Air Force’s RCRA permit application, with Justice Gorsuch remarking that overlapping review requirements does not mean that the two laws conflict. The Court’s ruling may then open the door to challenging federal agency RCRA permit applications that do not properly account for NEPA review. However, such a ruling is may be contingent on the Court holding that permit renewal is a reviewable final agency action. 

Hoffmann v. WBI Energy Transmission, Inc.

Under the Natural Gas Act, private companies are authorized to condemn land to build pipelines and other natural gas infrastructure. However, federal circuit courts have split on whether the just compensation owed to owners of condemned land must be determined according to state law (Third, Fifth, Sixth, and Eleventh Circuits) or by following the minimum compensation required by the Fifth Amendment (Eighth Circuit).[9] Petitioner Leonard W. Hoffmann is a North Dakota landowner seeking to recover costs incurred during a condemnation proceeding against Respondent WBI, a gas pipeline company. While North Dakota law requires condemnors to pay landowners’ eminent domain proceeding costs (including attorney’s fees) as part of their just compensation, federal law generally holds that landowners must bear their own costs. 

Hoffman has argued that the Natural Gas Act’s silence on just compensation payments indicates that Congress intended for state law compensation rules apply.[10] On the other hand, WBI maintains that Congress intended for federal standards regarding just compensation to apply and that determining just compensation by refence to state law would destroy the Natural Gas Act’s purpose of uniform national pipeline regulation.[11] The Court will hear oral arguments on November 9. Its decision in the case may determine how costs are borne among natural gas pipeline owners and owners of condemned land in certain states and, in turn, how and where gas pipelines are built.

For more information, please contact Zachary Zahner or David Uhlmann, who are based in Marten Law’s Washington, D.C. office. 

[1] No. 25-170, https://tinyurl.com/wxu96jah. 

[2] No. 25-579, https://tinyurl.com/33basbca. 

[3] No. 25-159, https://tinyurl.com/3dz4kn5m. 

[4] County Commissioners of Boulder County v. Suncor Energy USA, Inc., No. 24SA206 (Col. May 12, 2025), https://tinyurl.com/3em82th9.

[5] Petition for Writ of Certiorari, Suncor Energy Inc. v. County Commissioners of Boulder County, No. 25-170 (August 8, 2025), https://tinyurl.com/vtds8mbp, Brief for the Petitioners, Suncor Energy Inc. v. County Commissioners of Boulder County, No. 25-170 n(May 14, 2026), https://tinyurl.com/mpan7ccb. 

[6] Brief for the Respondents, Suncor Energy Inc. v. County Commissioners of Boulder County, No. 25-170 (July 27, 2026), https://tinyurl.com/53ynmaxm.

[7] Brief for the Petitioners, Department of the Air Force v. Prutehi Guåhan, No. 25-579. (May 22, 2026), https://tinyurl.com/yc5avm2z. 

[8] Brief for the Respondent, Department of the Air Force v. Prutehi Guåhan, No. 25-579 (July 20, 2026), https://tinyurl.com/2tx2m88x 

[9] Compare Tenn. Gas Pipeline Co. v. Permanent Easement for 7.053 Acres, 931 F.3d 237 (3d Cir. 2019), Ga. Power Co. v. 138.30 Acres, 617 F.2d 1112 (5th Cir. 1980), Columbia Gas Trans. Corp. v. Exclusive Nat. Gas Storage Easement, 962 F.2d 1192 (6th Cir. 1992), and Sabal Trail Trans., LLC v. 18.27 Acres of Land, 59 F.4th 1158 (11th Cir. 2023), with Hoffman v. WBI Energy Transmission, Inc. v. 189.9 rods, more or less, 132 F.4th 1058 (8th Cir. 2025). 

[10] Brief for the Petitioners, Hoffmann v. WBI Energy Transmission, Inc., No. 25-159 (August 13, 2026), https://tinyurl.com/yv46ctfs. 

[11] Brief for the Respondent, Hoffmann v. WBI Energy Transmission, Inc., No. 25-159 (September 14, 2026), https://tinyurl.com/544324br/