TagSustainable Airport Master Plan(280)

Appendix K of this environmental review examines socioeconomic conditions, environmental justice, and children's health and safety risks in the area surrounding the proposed project. It finds that 23.3% of the population in the study area is under 18—higher than both King County and statewide averages—and identifies two schools within the project boundary that could expose children to environmental health risks. The appendix also includes an economic impact analysis for the Northwest Seaport Alliance and a separate environmental justice memorandum prepared under Washington State's environmental review process.

The National Marine Fisheries Service (NMFS) issued a Biological Opinion on July 28, 2025, in response to a Federal Aviation Administration (FAA) consultation request regarding the Seattle-Tacoma International Airport Sustainable Airport Master Plan Near-Term Projects. The opinion evaluates potential effects of the planned airport projects on endangered species and critical fish habitat under the Endangered Species Act and the Magnuson-Stevens Fishery Conservation and Management Act. The review drew on a Final Biological Evaluation prepared by the FAA to assess impacts on species status, critical habitat, and the surrounding environment.

The National Marine Fisheries Service (NMFS) issued a Biological Opinion on July 28, 2025, in response to a Federal Aviation Administration consultation request regarding near-term construction projects outlined in the Seattle-Tacoma International Airport Sustainable Airport Master Plan. The opinion evaluates potential effects of these projects on endangered species and critical fish habitat under the Endangered Species Act and the Magnuson-Stevens Fishery Conservation and Management Act. NMFS reviewed and independently verified analyses from the FAA's Biological Evaluation, incorporating findings related to the proposed action area, species status, and effects on critical habitat.

The City of Des Moines, Washington submitted formal comments to the Port of Seattle in December 2024, raising concerns about the environmental and health impacts of Seattle-Tacoma International Airport's planned growth. The city warns that by 2032, annual flight operations will increase by nearly 20%, expanding the noise exposure zone and raising the number of residents affected by significant aircraft noise from roughly 14,000 to nearly 22,000—with most of that burden falling on Des Moines residents. The letter calls on the Port and FAA to extend public comment periods, pursue meaningful noise mitigation measures such as sound insulation for homes and schools, and engage more collaboratively with impacted communities rather than treating public review as a formality.