TagSEPA(293)

This draft Environmental Impact Statement (EIS) evaluates the potential environmental effects of near-term construction and expansion projects at Seattle-Tacoma International Airport, comparing a No Action Alternative against two action alternatives through a projected analysis year of 2032, with an out-year assessment extending to 2037. The study examines impacts across multiple environmental categories—including air quality, noise, greenhouse gas emissions, and surface transportation—using forecasted aircraft operations and passenger levels for each alternative. Mitigation and minimization measures are identified to address any significant adverse impacts identified through the analysis.

The Port of Seattle has released a Draft Environmental Impact Statement (EIS) under Washington State's environmental review law for 31 near-term construction projects at Seattle-Tacoma International Airport (SEA). The projects, which include a new 19-gate terminal and an elevated busway system, are designed to handle up to 56 million passengers by 2032. While a prior federal review found no significant environmental impacts requiring mitigation except for surface transportation, this state-level review evaluates two action alternatives alongside a no-action scenario.

This section of the May 2026 Draft Environmental Impact Statement for Seattle-Tacoma International Airport examines how the airport's near-term construction projects may combine with other past, present, and planned developments to create cumulative environmental effects. The analysis covers 58 projects in the surrounding area—including housing, road improvements, and airport expansions—completed or expected between 2017 and 2032, within a study area defined by the airport grounds, the 65 DNL noise contour, and the surface transportation zone. Long-term airport expansion proposals beyond 2032 are excluded from the analysis because they lack sufficient detail and funding approval to allow meaningful review.

The Port of Seattle has released a Draft Environmental Impact Statement for its Sustainable Airport Master Plan (SAMP), outlining 31 near-term construction projects at Seattle-Tacoma International Airport aimed at handling a projected 56 million passengers by 2032. Key proposals include a second terminal with 19 new aircraft gates, an elevated busway connecting terminals, expanded cargo facilities, airfield safety upgrades, and new sustainable aviation fuel infrastructure. The plan addresses longstanding capacity shortfalls in parking, check-in, security, and gate areas that were already undersized as of 2018.