## Facts

- Homer and Louis (Lois) Branch owned surface land allegedly contaminated by defendants’ oil-field operations, including wells and salt-water pits.
- Plaintiffs alleged pollution of surface and subsurface soil and water.
- Plaintiffs asserted, among other theories, unjust enrichment and a claim seeking abatement of a public nuisance against Citation Oil and Gas Corp.
- Citation moved to dismiss those two claims under Federal Rule of Civil Procedure 12(b)(6).
- The court initially granted the motion under a local rule because plaintiffs did not timely respond.
- Plaintiffs sought reconsideration, asserting the response deadline was extended because Citation served the motion by mail.
- The court vacated its earlier dismissal and addressed the motion to dismiss on the merits.

## Issues

1. Whether the court should vacate its earlier default dismissal because service by mail extended plaintiffs’ response deadline under the local rules and Federal Rule of Civil Procedure 6(e).
2. Whether plaintiffs stated an Oklahoma-law claim for unjust enrichment where the alleged “benefit” to defendants was avoided costs from using plaintiffs’ property for waste disposal.
3. Whether plaintiffs stated a claim for abatement of a public nuisance under Oklahoma nuisance and pollution statutes based on alleged contamination of soil and water.

## Decision

- The court vacated its earlier order dismissing the claims by default because the response time was extended due to service by mail.
- The court denied Citation’s Rule 12(b)(6) motion as to unjust enrichment, holding the complaint sufficiently alleged a form of “negative” unjust enrichment.
- The court denied Citation’s Rule 12(b)(6) motion as to public nuisance, holding the allegations and cited Oklahoma statutes supported a plausible claim for abatement at the pleading stage.

## Legal Principles

- When a motion is served by mail, the time to respond is extended under Federal Rule of Civil Procedure 6(e) and applicable local rules; a dismissal entered before the extended deadline may be vacated.
- Oklahoma unjust enrichment may be based on a defendant’s unjust savings (“negative unjust enrichment”), including cost avoidance achieved through unauthorized use of another’s property.
- On a Rule 12(b)(6) motion, the court assesses whether the complaint plausibly states a claim; allegations that defendants used plaintiffs’ land to dispose of pollutants and thereby avoided disposal costs can satisfy the “benefit” element for restitution purposes.
- Allegations of pollution affecting soil and waters can support a statutory and common-law claim seeking abatement of a public nuisance under Oklahoma law at the pleading stage.

## Conclusion

The court set aside a default dismissal entered before plaintiffs’ mail-extended response deadline and held that allegations of oil-field contamination plausibly supported claims for negative unjust enrichment and abatement of a public nuisance, allowing those counts against Citation to proceed past Rule 12(b)(6).


Branch v. Mobil Oil Corp., 778 F. Supp. 35 (W.D. Okla. 1991)