Ninth Circuit Provides Airports with a Significant Defense to State Law Emissions Claims
The Ninth Circuit has reversed a District Court decision and held that the Clean Air Act expressly preempts state-law claims seeking relief for pollutants emitted directly by aircraft. The decision gives airports and airlines a potentially significant defense to claims arising from aircraft emissions. Codoni v. Port of Seattle, No. 25-2830 (9th Cir. Sept. 23, 2026)
Residents Challenge Aircraft Pollution Near Sea-Tac Airport
The case originated with five residents living beneath flight paths near Seattle-Tacoma International Airport who brought a proposed class action against the Port of Seattle (which owns and operates the airport), Alaska Airlines and Delta Air Lines. They alleged that aircraft exhaust and particles from aircraft bodies contaminated surrounding air and soil, asserting state-law claims for negligence, battery, trespass, public nuisance and inverse condemnation. The residents sought damages, remediation, medical monitoring and injunctive and declaratory relief.
The complaint named the airport as a defendant on the theory that it permitted the airlines’ takeoffs and landings, which allegedly generated pollution from aircraft engine exhaust and aircraft fuselages. The court held that both the exhaust and fuselage particles were air pollutants because they entered and dispersed through the surrounding air. That distinction is important because it brought both claims within Section 233’s preemptive scope.
Clean Air Act Preempts State-Law Standards Addressing Aircraft Emissions
The Ninth Circuit held that Section 233 of the Clean Air Act prohibits a state or political subdivision from adopting or enforcing any "standard respecting emissions of any air pollutant from any aircraft or engine" unless that standard is identical to an applicable federal standard.
Drawing on decisions interpreting similar federal preemption provisions, the Ninth Circuit concluded that a state-law "standard" includes common-law rules and duties, not merely statutes and regulations. Because the residents' tort and state constitutional claims sought to enforce state-law duties respecting pollutants emitted directly from aircraft and aircraft engines, the claims were preempted.
The residents argued that their claims concerned only the failure to clean up pollutants after they reached the ground. The Ninth Circuit rejected that distinction, reasoning that Section 233's use of "respecting" reaches duties related to the original aircraft emissions. Recasting the alleged wrong as on-the-ground contamination or a failure to remediate did not avoid preemption.
Although the airport did not operate the aircraft, the Ninth Circuit held the claims against it were preempted because the complaint alleged that the airport permitted the activities generating the emissions.
What the Decision Means for Airports
Codoni provides a strong basis for an airport to seek dismissal of state-law claims that seek to impose liability for pollutants released directly into the ambient air from aircraft bodies or engines during flight operations. However, a separate analysis would be required for claims involving independent sources such as fuel spills, stormwater, deicing runoff, construction, stationary facilities or ground-support equipment.
For guidance on how Codoni may affect airport liability for aircraft emissions, potential defenses to state-law environmental claims or claims involving other sources of airport pollution, contact your BBK attorney or Chandley Hayes-Crawford and Thomas Rice.
