TagNEPA(463)

The 1997 Sea-Tac International Airport Impact Mitigation Study is an initial assessment and recommendations report prepared for several cities near Seattle-Tacoma International Airport, including Burien, Des Moines, Federal Way, Normandy Park, and Tukwila, as well as the Highline School District and Highline Community Hospital. Funded by a State of Washington grant, the study was conducted by Hellmuth, Obata + Kassabaum, Inc. and Raytheon Infrastructure Services, Inc. to evaluate the airport's impacts on surrounding communities. The report was submitted as part of public engagement materials related to ongoing concerns about airport noise and air pollution affecting nearby residents and institutions.

Appendix O of the Sustainable Airport Master Plan (SAMP) Environmental Assessment documents how the FAA engaged the public and agencies during the NEPA review process for Sea-Tac Airport, including public meetings, briefings, and outreach to communities, elected officials, and underrepresented groups. The summary notes that several Executive Orders and CEQ regulations referenced during the Draft EA have since been revoked, and that the FAA's final decision will rely on updated federal guidance including FAA Order 1050.1F and Executive Order 14154. Public comments received and submitted studies are also included as part of this appendix.

The City of SeaTac hired the law firm Ogden Murphy Wallace, P.L.L.C. to serve as special environmental counsel, representing the city in the environmental review processes under NEPA and SEPA related to the Port of Seattle's Sustainable Airport Master Plan. The engagement, dated September 10, 2025, also covers any litigation that may arise against the Port or the Federal Aviation Authority in connection with the plan. Legal services are billed at hourly rates ranging from $300 to $535 depending on the level of attorney or staff involved.

This September 2025 Environmental Assessment evaluates three alternatives for near-term development projects at Seattle-Tacoma International Airport, comparing a No Action scenario against a Proposed Action and a Hybrid Terminal Option through analysis years 2032 and 2037. The study finds that while both action alternatives would increase aircraft operations to approximately 475,655 by 2032 and 509,892 by 2037, resulting in higher emissions and some biological resource impacts, none of the increases are considered significant. Mitigation measures, where warranted, include post-construction stormwater controls and nest protection protocols during construction activities.