## Facts

- American Smelting and Refining Company (ASARCO) operated a primary copper smelter in Ruston, Washington, emitting sulfur dioxide and particulate matter, including heavy metals such as arsenic and cadmium.
- Landowners on Vashon Island, including Michael and Marie Bradley, owned residential property about four miles north of the smelter.
- The Bradleys bought their property in 1978 and alleged that microscopic airborne metal particulates from the smelter were deposited on their land, causing damage.
- The landowners sued in federal district court in 1983, asserting intentional trespass and nuisance based on particulate deposition.
- The parties stipulated to facts and filed cross-motions for summary judgment; the federal court certified questions of Washington law to the Washington Supreme Court.

## Issues

1. Whether ASARCO had the requisite intent for an intentional trespass where it emitted particulates that it knew would be carried onto surrounding lands.
2. Whether intentional deposition of microscopic particulates, undetectable by human senses, can constitute trespass (interference with exclusive possession) as well as nuisance (interference with use and enjoyment).
3. Whether a trespass claim based on airborne industrial pollution requires proof of actual damages, or whether nominal damages are available absent substantial harm.
4. What limitations and defenses apply, including the statute of limitations/accrual rules, continuing-trespass concepts, prescriptive easement, and statutory preemption under the Washington Clean Air Act.

## Decision

- The court concluded ASARCO had the intent required for intentional trespass because it knew with substantial certainty that smelter emissions would contaminate surrounding lands.
- The court held microscopic particulate deposits can support a trespass claim when they interfere with the plaintiff’s right to exclusive possession, not merely a nuisance claim.
- The court held plaintiffs must prove a nontransitory invasion and actual, substantial damages to maintain a pollution-based trespass claim; nominal damages are not available as of right.
- The court indicated the three-year statute of limitations for trespass applies and runs from accrual rather than discovery of injury.
- The court stated a prescriptive-easement defense was unlikely because microscopic particulate invasions are not typically open and notorious.
- The court rejected statutory preemption, concluding the Washington Clean Air Act does not bar common-law damages actions.

## Legal Principles

- Intent for intentional trespass is satisfied when the defendant acts with knowledge to a substantial certainty that its conduct will result in an invasion of another’s property, even without a purpose to invade a specific parcel.
- The trespass/nuisance line turns on the interest invaded: trespass protects exclusive possession; nuisance protects use and enjoyment; microscopic particles may constitute trespass if they settle and remain.
- In airborne industrial pollution cases, trespass requires (1) a nontransitory physical invasion and (2) actual, substantial damages to the possessory interest; mere deposition without substantial harm is insufficient.
- Trespass claims are governed by the three-year limitations period, accruing when the invasion causes harm rather than when the harm is discovered.
- Prescriptive rights generally require an open and notorious use; invisible or undetectable particulate invasions ordinarily do not satisfy that requirement.
- Environmental regulation under the Washington Clean Air Act does not displace common-law tort remedies for damages absent clear legislative intent to preempt.

## Conclusion

Washington recognized that settled microscopic industrial particulates can constitute trespass as well as nuisance, but limited pollution-based trespass to cases showing a nontransitory invasion and actual, substantial damage, while applying a three-year accrual-based limitations period and rejecting Clean Air Act preemption and (typically) prescription defenses for undetectable invasions.


Bradley v. Am. Smelting & Ref. Co., 104 Wn.2d 677, 709 P.2d 782 (Wash. 1985)