## Facts

- For decades, operation of the Anaconda Copper Smelter in Montana released arsenic and lead, contaminating a large area.
- The Environmental Protection Agency (EPA) placed the area on the National Priorities List as a Superfund site and began a long-term cleanup under CERCLA.
- Atlantic Richfield, as current owner of the site, worked with EPA to implement an EPA-approved remedial plan projected to continue for years.
- Ninety-eight landowners whose properties were within the Superfund site sued Atlantic Richfield in Montana state court on state common-law theories (nuisance, trespass, strict liability).
- The landowners sought “restoration damages,” which under Montana law must be used to restore the properties.
- The landowners’ proposed restoration measures went beyond EPA’s selected remedy (e.g., additional soil removal and deeper barriers).
- Atlantic Richfield argued (1) CERCLA barred the suit as an impermissible “challenge” to the EPA cleanup plan and (2) landowners were “potentially responsible parties” (PRPs) who could not undertake additional remedial action without EPA approval under CERCLA § 122(e)(6).

## Issues

1. Whether CERCLA strips state courts of jurisdiction over, or otherwise bars, state-law restoration-damages claims concerning property within a Superfund site as a prohibited “challenge” to EPA’s remedial action.
2. Whether landowners within a Superfund site are PRPs, and if so, whether CERCLA § 122(e)(6) requires EPA approval before they can undertake remedial actions beyond the EPA-selected remedy.

## Decision

- The Supreme Court affirmed in part, vacated in part, and remanded.
- The Court held that CERCLA does not strip state courts of jurisdiction over the landowners’ state-law claims and does not categorically preempt those claims.
- The Court held that the landowners are PRPs because they own property within the facility where hazardous substances have come to be located.
- Because the landowners are PRPs, the Court held that CERCLA § 122(e)(6) bars them from undertaking remedial action beyond the EPA-approved plan without EPA approval.
- The Montana Supreme Court was correct on state-court jurisdiction but wrong in concluding the landowners were not PRPs and thus not subject to § 122(e)(6).

## Legal Principles

- CERCLA § 113(b)’s grant of exclusive federal jurisdiction over controversies “arising under” CERCLA does not extinguish or relocate state-law causes of action that arise under state law.
- CERCLA § 113(h) limits federal-court jurisdiction over “challenges” to removal or remedial action but does not, by its text, withdraw state-court jurisdiction.
- CERCLA contemplates the continued availability of state-law claims, including claims by private parties seeking damages.
- “Potentially responsible parties” include current owners of facilities where hazardous substances are located, regardless of fault; statutory defenses may defeat liability but do not negate PRP status.
- Under CERCLA § 122(e)(6), once the remedial investigation and feasibility study process is underway, PRPs may not undertake remedial action at the facility without EPA approval.
- State-law restoration remedies may be pursued, but any additional cleanup work at a Superfund site that qualifies as “remedial action” must proceed consistently with CERCLA’s EPA-controlled cleanup process.

## Conclusion

State courts may hear state common-law claims seeking restoration damages for property within a Superfund site, but landowners within the site are PRPs and therefore must obtain EPA approval before implementing remedial measures that go beyond the EPA-selected cleanup plan.


Atlantic Richfield Co. v. Christian, 140 S. Ct. 1335 (2020)