Three cities near Seattle-Tacoma International Airport — SeaTac, Des Moines, and Burien — are challenging a September 2025 FAA decision that declared a major airport expansion plan would have no significant environmental impact. The cities argue the FAA's environmental review was legally flawed because it used an artificially narrow baseline, ignored cumulative effects, and underestimated impacts on noise, air quality, and traffic in surrounding communities. The case is being heard in the Ninth Circuit Court of Appeals alongside a related challenge brought by Vashon Island Fair Skies, with the FAA seeking to consolidate both cases.Open full document
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A mediation questionnaire filed in the Ninth Circuit Court of Appeals challenging the FAA’s September 2025 FONSI/ROD for Seattle-Tacoma International Airport Sustainable Airport Master Plan Near-Term Projects. The Cities contend the FAA’s environmental review violated NEPA by using an artificially truncated environmental baseline and failing to assess cumulative impacts.