Notes
Chapter 4 of the Final Environmental Assessment (EA) for Seattle-Tacoma International Airport (Sea-Tac Airport) Sustainable Airport Master Plan (SAMP) near-term projects, published September 2025 by Port Of Seattle. Presents environmental consequences for Alternative 1 (No Action), Alternative 2 (Proposed Action), and Alternative 3 (Hybrid Terminal Option) for analysis years 2032 and 2037. Covers forecasted aircraft operations (466,900–509,892) and passenger levels (57–64 million) by alternative. Table 4-2 summarizes impacts and mitigation for Air Quality (criteria pollutants, construction and operational emissions) and Biological Resources (Chinook salmon, Steelhead, Bull trout, Bocaccio rockfish, Yelloweye rockfish, Killer whale, 56.4 acres of migratory bird habitat, stormwater runoff, industrial wastewater). Farmlands and Wild and Scenic Rivers excluded as not present in GSA. Conducted under FAA Order 1050.1F; NEPA environmental assessment process.