The SeaTac Airports Community Coalition for Justice (STACC4J), together with the coalition partners listed above, asks the Port to withdraw and revise the Draft Environmental Impact Statement (DEIS) or issue a Supplemental DEIS before proceeding to a Final EIS. The current document does not give the Port's Commissioners, the cities living with the airport's operations, or the residents in this coalition a true picture of who bears the burdens of the SAMP Near-Term Projects.

Most areas around SeaTac Airport (SEA) already score 7 to 10 on Washington’s Environmental Health Disparities map, with many at 9 or 10. A DEIS that reaches “no disproportionate and adverse effects” on communities the state itself has already identified as carrying disproportionate harm is not a reliable picture.

What the DEIS gets wrong:

It draws its map too small. The DEIS studies impacts inside a fenceline drawn close to the airport. Pollution does not stop at the airport fence. Planes fly over homes and schools. Trucks use neighborhood streets. Rain carries pollution into creeks. The Port should study the places where those impacts travel, not only on land it owns.

Uses the wrong yardstick. The Port mostly asks whether pollution stays below broad federal limits. But people do not live in an average. They live near flight paths, truck routes, schools, and creeks, and try to have conversations between planes. The Port should show what SAMP projects adds in the neighborhoods that will actually receive the pollution, noise, traffic, and runoff.

It leaves too much for later. The DEIS points to future permits for projects but does not clearly say what will be studied later, who will study it, when that will happen, or whether the public will get to weigh in. “We will deal with it later” is not enough.

To meet SEPA’s adequacy standard, the Final EIS must do seven things:

1. Expand the study area to match the pollution footprint. Analyze the impacts across flight-funnel and freight/cargo corridors, warehouse buildout areas, and the affected watersheds—not just Port-controlled properties. Include Burien, SeaTac, Tukwila, Des Moines, Federal Way, Normandy Park, unincorporated south King County, the Duwamish Valley, Beacon Hill, Georgetown, and South Park.

2. Analyze cumulative environmental and health impacts using Washington’s environmental justice tools. Integrate the Environmental Health Disparities Map, disaggregate exposure and outcome data by community, and analyze how SAMP interacts with the SR-509 completion, the North of NERA rezone, and the surrounding freight and industrial corridors. SEPA requires cumulative analysis under WAC 197-11-060(4)(d) and WAC 197-11-792 whether or not federal cumulative impact frameworks apply.

3. Use significance thresholds calibrated to the neighborhoods, not to regional averages. For air quality, apply Ecology’s proposed screening values under Chapter 173-400 WAC and analyze ultrafine particles (UFPs)—which are extremely small particles from aircraft and vehicle exhaust. They can travel deep into the lungs, but the DEIS does not measure or analyze them. For noise, replace the 1.5 dB DNL threshold with a WHO/EPA population exposure analysis. For water, apply the 2024 6PPD-quinone Water Quality Criterion, the 2025 Industrial Stormwater General Permit, and the 2024 Stormwater Management Manual.

4. Explain how water impacts will be reviewed and disclose the permitting pathway and the post-Sackett jurisdictional analysis. A permit is not just paperwork. The permit path the Port chooses affects who reviews the project, what gets studied, and when the public can speak up. The Port should explain, project by project, which permits it will use, which agency will review them, and whether each project will receive its own water quality review. And if the Port intends compensatory wetland mitigation where it’s needed, or whether that work will move out-of-basin to the Port’s Auburn “bank.”

5. Show how Tribal governments were engaged, and fill Appendix O. The Muckleshoot Indian Tribe, the Suquamish Tribe, and any other Tribes with treaty reserved resources in the affected watersheds must be engaged under the Governor’s Executive Order 21-02, the Centennial Accord, and the Port’s own MOAs. Publication of a DEIS is not consultation. Appendix O is currently blank and it sits on top of a federal Section 106 record that shows no outreach to the Muckleshoot Indian Tribe.

6. Identify each analysis being deferred to a downstream permit, and to which permit. Under WAC 197-11-060(5) and WAC 197-11-440(6), the Port must disclose each deferred analysis, which specific permit would address each, the responsible agency, the expected timing, and the regulatory framework that will govern. SEPA based mitigation cannot rest on undisclosed impacts even as downstream agencies retain their own independent authority.

7. Attach concrete, funded, enforceable mitigation to each significant impact. Under WAC 197-11-660(1)(b), mitigation must be tied to specific disclosed impacts, matched to the neighborhoods where the impact lands, and include timelines, funding sources, performance standards, public reporting, independent monitoring, and consequences for non-performance. Vague promises are not mitigation.

We are a coalition of community organizations and residents in airport impacted communities: SeaTac, Burien, Des Moines, Normandy Park, Tukwila, and neighborhoods under the SEA flight paths that include Beacon Hill, Georgetown/South Park, Allentown, and the Duwamish Valley. Our members live and work under constant aviation noise, ultrafine‑particle (UFP) exposure, diesel and toxic tire dust (6PPD-Q) pollution from heavy truck traffic tied to airport cargo and freight, tree canopy loss and the rise of heat islands, all leading to alarming health disparities, as well as rising rents and concerns on affordability driven by airport adjacent industrial growth.

These comments reflect three years of resident conversations, a 2024–25 working group of 20 grassroots organizations, our 2024 comments on the FAA's NEPA Environmental Assessment for SAMP Near‑Term Projects, community‑led research and collaboration, commitments made publicly by Port Commissioners and state legislators at the October 17, 2025 Election Forum, and conversations at the June 19, 2026 STACC4J-hosted event.

Our core position: The Draft EIS as currently written does not meet SEPA's requirements. Each objection below corresponds to a specific procedural or substantive obligation under the State Environmental Policy Act (RCW 43.21C, WAC 197-11).

Washington’s Environmental Health Disparities (EHD) map scores every neighborhood in the state from 1 to 10 based on cumulative pollution exposure, health outcomes, and social vulnerability. If your neighborhood scores 9 or 10, you are already carrying some of the heaviest pollution, health, and economic burdens in Washington. “The project stays under a national average threshold” is no answer to whether it will make things even worse for you.

Appendix K (Environmental Justice, Socioeconomics, and Children’s Health) does two contradictory things. It confirms that most census tracts around SEA score 7 to 10 on the EHD map, with many at 9 or 10. In the same document, the Port then adopts the FAA’s EA conclusion that SAMP will cause “no disproportionate and adverse effects” on those communities. But a community at 9 or 10 is by definition already carrying disproportionate harm. Adding a tripling of air cargo, 31 near-term projects, cumulative traffic and warehouse growth, and canopy loss on top of that population and then declaring “no disproportionate and adverse effects”  is not supported by the Port’s own facts.

Why this is a SEPA problem, not just a moral one.

Washington’s State Environmental Policy Act (SEPA) is broader than the federal thresholds the Port is leaning on. RCW 43.21C.010 states the whole point of SEPA is to “prevent or eliminate damage to the environment and biosphere” while promoting human welfare. WAC 197-11-448 confirms that federal attainment is a floor, not a ceiling on what SEPA requires. As lead agency, the Port has the authority under RCW 43.21C.060 to condition or reject actions that would worsen conditions in already overburdened communities, even if the action would technically pass federal numeric thresholds.

The Final EIS must revisit its significance determinations against SEPA's standard, not the FAA’s. Where the state’s EHD data show communities already at 7 to 10, the final EIS needs to look harder, not less hard. In neighborhoods already carrying high pollution and health burdens, the Final EIS should take a closer, neighborhood by neighborhood look at what SAMP adds. It should explain, with independent, community verified data, whether conditions are expected to improve, stay the same, or get worse. ‘It stays under a federal average’ is not an answer.

Ask a resident of Burien and they will say the air near the airport is getting worse. The DEIS says nope. The gap between those two answers is not about the data. It is about which test the Port used.

The test the Port ran is not the test SEPA requires. The federal air quality test asks a regional question: does pollution across a large region stays below a legal limit?  That matters, but SEPA asks a neighborhood question: What extra pollution will people in Boulevard Park, Beacon Hill, or other nearby communities breathe because of this project? Does this project add unequal harm to communities already carrying more than their share? The Port answered the regional question and called it an answer to the neighborhood question.

Under WAC 197-11-330(3), a SEPA significance determination has to look at the context and intensity of the impact for the specific community affected, including whether the area is already unusually sensitive and whether approving the project will set a pattern for the next one. The federal National Ambient Air Quality Standards (NAAQS) are a regional attainment test, not a SEPA significance test, and the absence of a federal standard does not equal ‘no significant impact.’ In other words, if SEPA’s question is, “Will this hurt Boulevard Park or Beacon Hill?” and the DEIS's response is, “Regional air quality still meets federal standards,” that is not an answer.

The Port's own numbers show why the neighborhood question matters. DEIS Chapter 4, Table 4.3.1-10 reports how much air pollution the project would add. For nitrogen dioxide (NO₂, a traffic and jet engine pollutant tied to asthma and lung disease) the project adds a peak of 22 micrograms per cubic meter over one hour or nearly 3x Ecology’s screening value, the amount big enough to trigger a closer look. For fine particulate matter (PM2.5, tiny particles that lodge deep in the lungs and are linked to heart disease and premature death) it adds 0.5 micrograms per cubic meter as a yearly average—almost 4x Ecology’s screening threshold.

Those thresholds are permitting screens, however, not SEPA significance tests. An EIS that never engages with the size of its own reported increment is not a significance analysis. It is a federal attainment check. The DEIS makes this clear: page 4-9 states that “the total concentrations (increment plus background) were then compared to the NAAQS to determine if an impact could occur.” Table 4.3.1-10 executes exactly that test—its rightmost column is titled “Exceed NAAQS?” and every row answers “No.” That is the only significance test the table shows. Under WAC 197-11-448, that is not enough.

Two more things the DEIS record does not show. First, EPA tightened the federal PM2.5 standard in 2024—from 12 down to 9 µg/m³. Any Ecology permit issued during SAMP construction will be issued under the tighter number, not the number the DEIS modeled against. Second, the Port has already told a court exactly what airport adjacent housing suffers from. 

On June 24, 2026, the Port filed a motion before the Seattle Hearing Examiner (File W-26-001) opposing a City of Seattle plan that would have allowed new housing near industrial and freight operations. The Port argued that mixing homes with “active industrial and freight corridors” would cause “truck traffic, rail and port operations, nighttime activity, noise, emissions, safety, and pressure to limit or modify industrial operations.” The Port told the court these concerns were “not academic, theoretical, or hypothetical.”

Read that list again. It is exactly what residents of Burien, SeaTac, Des Moines, Tukwila, and unincorporated King County already live with every day because of the airport, SR-509, and the freight corridors the SAMP will help expand.  The Port has recognized that hypothetical homes near major freight and industrial activity can face real problems from trucks, noise, emissions, nighttime activity, and safety risks. Real residents near SEA already live with those conditions. The Final EIS should use the same level of care when studying the people who are already there.