The opinion was nearly unanimous, with Chief Justice Roberts writing the opinion in which Justices Ginsburg, Breyer, Sotomayor, Kagan, and Kavanaugh joined, and Justices Alito, Gorsuch, and Thomas concurred in part and dissented in part.

The case involves a Superfund site located in Butte, Montana, which spans over 300 square miles and is contaminated with lead and arsenic originating from three historic copper smelters owned by the Atlantic Richfield Company (ARCO). EPA has been working with ARCO for the last 35 years to clean up the site, and remedial projects are expected to continue through 2025.

In 2008, 98 private landowners with property located within the boundaries of EPA’s site sued ARCO in Montana state court for common law nuisance, trespass, and strict liability, seeking, among other remedies, restoration damages to remediate their properties. As part of the litigation, the landowners submitted a proposed restoration plan for their properties that conflicted with—and went beyond—EPA’s site-wide cleanup plan. The Montana courts found that the landowners’ lawsuit could proceed in state court.

ARCO raised three questions in its petition for certiorari to the Supreme Court:

1. Whether a state common-law claim seeking cleanup remedies that conflict with EPA-ordered remedies is a “challenge” to EPA’s cleanup and is jurisdictionally barred by § 113(b) & (h) of CERCLA;

ANSWER: No.

2. Whether a landowner at a Superfund site is a “potentially responsible party” that must seek EPA’s approval under CERCLA § 122(e)(6) before engaging in remedial action, even if EPA has never ordered the landowner to pay for a cleanup; and

ANSWER: Yes.

3. Whether CERCLA preempts state common law claims for restoration that seek cleanup remedies that conflict with EPA-ordered remedies.

ANSWER: Not answered. (“In the absence of EPA approval of the current restoration plan, we have no occasion to entertain Atlantic Richfield’s claim that the Act otherwise preempts the plan.”) However, the Court did reject an argument that Justice Gorsuch advanced in his separate opinion that CERCLA’s saving clauses prevented application of §122(e)(6) to claims brought under state law.

The Court remanded the case for further proceedings.

Discussion

State Courts Have Jurisdiction to Hear Non-CERCLA Claims

CERCLA provides exclusive federal jurisdiction over actions “arising under” the statute. 42 U.S.C. § 9613(b) (“[T]he United States district courts shall have exclusive original jurisdiction over all controversies arising under [CERCLA].”) Further, CERCLA states that federal courts are deprived of jurisdiction over any claims constituting a “challenge” to a CERCLA cleanup while that cleanup is ongoing. 42 U.S.C. § 9613(h) (“No Federal court shall have jurisdiction under Federal law ... or under State law ... to review any challenges to removal or remedial action....”).

Many circuit courts have historically read §113(h) together with §113(b) to conclude that state courts also lack jurisdiction over any claims that constitute “a challenge to a CERCLA cleanup,” whether arising under CERCLA or any other state or federal law.

The Supreme Court held that §113(b) only grants exclusive jurisdiction to federal courts for CERCLA actions; federal courts are not granted exclusive jurisdiction over actions that may relate to CERCLA sites but arise under other laws. According to the Court, “[t]he Act does not strip the Montana courts of jurisdiction over this lawsuit... it does not displace state court jurisdiction over claims brought under other sources of law.” ARCO v. Christian, slip op. at 8-9. Thus, state courts have jurisdiction to hear common law trespass and nuisance claims that relate to CERCLA sites because the claims do not “arise under” CERCLA.

Further, the Court held that §113(h) only deprives federal courts of jurisdiction to hear certain claims constituting challenges to CERCLA cleanups—state courts are not barred from hearing such claims. “[B]y its own terms, §113(h) speaks of ‘Federal court[s],’ not state courts. There is no textual basis for Atlantic Richfield’s argument that Congress precluded state courts from hearing a category of cases in §113(b) by stripping federal courts of jurisdiction over those cases in §113(h).” ARCO v. Christian, slip op. at 10-11 (emphasis in original).

The Court stated that the two provisions “work independent of one another.” ARCO v. Christian, slip op. at 13. This decision means that plaintiffs who have state law claims against a polluting defendant can bring those claims in state courts (or in federal courts sitting in diversity cases) even if the claims constitute a “challenge” to an ongoing CERCLA cleanup.

Section 122(e)(6) Applies to All “PRPs” at Superfund Sites

Although the Court found that the Montana state court had jurisdiction to hear the landowners’ state property and tort claims, the remedy sought by the plaintiffs was not permissible absent approval from EPA for the proposed restoration plan. CERCLA § 122(e)(6) provides that responsible parties cannot take remedial action absent EPA approval.

It is important that the Court has clarified that, for purposes of §122(e)(6), a PRP can be a person against whom the EPA has never brought a claim, as well as a person against whom EPA can or will never bring a claim due to the passing of the statute of limitations or EPA policy. According to the Court, broadly interpreting who can be considered a PRP reflects the basic purpose of CERCLA: to comprehensively address contamination. See ARCO v. Christian, slip op. at 15. However, the Court made clear that the bar under §122(e)(6) applies only to sites on the Superfund list. ARCO v. Christian, slip op. at 17. This raises the question of whether a PRP at a non-listed site would have the same limitation on remedies as the Plaintiffs in ARCO.

Preemption Remains a Viable Argument against Application of State Law

Although raised by ARCO in its petition for certiorari, the Court did not decide the preemption question. Conflict preemption occurs “when compliance with both state and federal law is impossible, or when the state law stands as an obstacle to the accomplishment and execution of the full purposes and objective of Congress.” United States v. Locke, 529 U.S. 89, 109, 120 S. Ct. 1135, 1148 (2000) (internal quotes omitted).

ARCO argued that imposing cleanup requirements that conflicted with EPA’s chosen remedy under CERCLA frustrated the purpose of the federal Act. While the Court declined to reach this issue, it did suggest that it does not view broad savings clauses in federal statutes as allowing for wholly inconsistent state laws to be enforced. “[W]e have long rejected interpretations of sweeping saving clauses that prove absolutely inconsistent with the provisions of the act in which they are found.” ARCO v. Christian slip op. at 19 (internal quotes omitted).

Consequently, this decision does not prevent defendants from arguing that additional or conflicting requirements imposed under state laws frustrate the purpose and objectives of CERCLA, and therefore are preempted.

Conclusion

In ARCO, the Court found a vehicle to clarify the jurisdiction and timing for “challenges” to CERCLA cleanups. This decision comes after many years of circuit courts broadly interpreting CERCLA’s provisions as barring all claims that related to an ongoing cleanup—regardless of the law under which the challenge was brought and regardless of which court it was brought before. ARCO shifts that paradigm and opens up a new avenue for plaintiffs to seek remedies from responsible parties without waiting decades for completion of an EPA-selected CERCLA remedy.

In practice, the ARCO decision may impede CERCLA settlements. A primary objective of CERCLA settlements is to achieve finality and certainty for the settling PRP, while providing for a comprehensive remedy protective of human health and the environment. If a settlement with EPA cannot halt piecemeal litigation of liabilities and conflicting cleanup requirements, settlement with PRPs may be much harder for EPA to achieve in the future.