TagNEPA(390)

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 The summary notes that several Executive Orders and CEQ regulations referenced during the Draft EA have since been revoked, and that the FAA's final decision will rely on updated federal guidance including FAA Order 1050.1F and Executive Order 14154.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.

Appendix O of the FAA NEPA Draft Environmental Assessment (EA) for the Sustainable Airport Master Plan (SAMP) at Sea-Tac Airport. Documents agency and public engagement activities during the EA process, including coordination under NEPA (42 U.S.C. 4321 et seq.), FAA Orders 1050.1F and 5050.4B, and CEQ regulations (40 CFR parts 1500-1508). Notes regulatory changes including

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 document is the References section of the Environmental Assessment for Seattle-Tacoma International Airport's Sustainable Airport Master Plan Near-Term Projects, finalized in September 2025. It lists all sources cited across the assessment's chapters, including federal regulations, FAA advisory circulars, technical memoranda, city comprehensive plans, and environmental studies used to evaluate the airport's proposed development projects. The referenced materials cover topics such as air quality, facility requirements, stormwater management, land use, and aviation activity forecasting.

The Final Environmental Assessment for Seattle-Tacoma International Airport's Sustainable Airport Master Plan near-term projects explains that cumulative impact analysis has been removed from the document. This change reflects recent legal developments, including the revocation of CEQ regulations implementing NEPA and a May 2025 Supreme Court ruling, which together mean federal agencies are no longer required to assess the combined environmental effects of separate but related projects. As a result, the section that previously contained cumulative impacts data and analysis is now absent from this final report.

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.

This section of the Seattle-Tacoma International Airport (SEA) Environmental Assessment describes the airport's physical setting and surrounding communities as they existed in 2022, serving as the baseline for evaluating potential impacts from near-term expansion projects. SEA occupies approximately 2,800 acres in the City of SeaTac, bordered by state routes and residential neighborhoods in cities including Burien, Des Moines, and Tukwila. The assessment defines a General Study Area of 3,692 acres where direct or indirect impacts from proposed actions may reasonably be expected to occur.

This section of the Seattle-Tacoma International Airport Environmental Assessment describes how planners evaluated different alternatives to the airport's near-term expansion projects, using a two-step screening process to determine whether each option met the project's stated goals and was practical to implement. Public suggestions submitted during the scoping process—such as building a new airport, using high-speed rail, limiting growth, or relying on other existing airports—were largely rejected because they could not meet current and future passenger demand at SEA. A No Action Alternative is also included, representing a future scenario in which none of the proposed new construction takes place.