Ideas and instructions for commenting on the Sustainable Airport Master Plan Near-Term Projects Draft Environmental Impact Statement (SAMP-NTP DEIS or just ‘SAMP’ for short.) If you don’t know what the SAMP is about, go here.
Why you should comment
Comment periods exist to give the public an opportunity to read a draft proposal of every major construction project and question the project(s), their possible harms, and possible mitigations, before it is allowed to be permitted.
As commenter, consider yourself as an editor of the DEIS. Your comments will be read by the people who wrote the DEIS, the people who will approve it, and anyone reviewing any subsequent appeal. Your job is to point out mistakes, find gaps, ask for more information where there isn’t enough, and question specific conclusions you think they got wrong. Your job is to make it a better, more complete review of the project. This is especially important because, if approved, the SAMP will be the largest expansion in airport history. And yet, the draft provides almost no mitigations for a third more new flights, noise, pollution, and other permanent community impacts!
How to use this
The problems we see in the document break down into three main themes: Segmentation, The Greater Good Argument, and Outdated standards.
- Use your own words–you may think of something no one else has. You don’t have to be lengthy, but duplicating what anyone writes word for word is wasted effort. Tell the Port where you live and how the issue affects you and your neighborhood.
- Focus on the following Comment Ideas. Use the links next to each item to study an idea in more detail. Remember: you’re trying to help edit a document, not only complain. Complaints without a direction connection to the document are politely noted, but not much more.
- Each item ends with an Ask. That is the important part! You’re an editor. A good comment points out where the document is insufficient and names where it needs further study. A specific Ask is what separates a comment from a complaint.
- Encourage the Port to work with local jurisdictions to develop a long term plan that is mutually beneficial to both the Airport and airport communities. Permanent, specific, and substantial mitigation plans need to be established for each community.
- Send in your comment by Monday, August 20, 2026, 5:00 PM. either at sea-samp.com/get-involved or email samp@portseattle.org (Mr. Steve Rybolt, Port of Seattle, AV Environment and Sustainability).
The Comment Ideas
Segmentation
The SAMP minimizes project impacts by breaking components into small pieces by time and place. This strategy avoids consideration of its full impacts.
#1 Not enough detail. The DEIS describes 31 projects at roughly 10% design. You cannot measure ongoing impacts of any major construction project from a drawing that isn’t finished. The Port is asking the public to approve a plan it hasn’t actually drawn yet. Ask: finish the design — to at least 30% — and re-issue the impact analysis for public review before any project is permitted. At 10% design the EIS cannot support its own conclusions. (More from STNI: the 31 projects by the numbers)
#2 Demolition with no detail. Buildings are slated to come down, some of them beyond the airport’s own property line, with no analysis of where the debris goes or what replaces them. Ask: describe each demolition — how it’s done, where the debris and any hazardous material go, what replaces the building, and under what permit — including the buildings that sit outside the airport’s property line.
#3 The study area does not match the impact area. In every aspect except water quality, the study area is limited to the AAA — the airfield. Broader impacts, such as noise and air pollution, are handed off to weak federal standards. Ask: use the Port’s own Century Agenda as the limit: a reduction of aircraft emissions by 25% from 2012 levels.
#4 The study area does not match the impact area. The study assumes that water quality testing on the airfield will adequately capture impacts throughout the watersheds — despite the fact that the AAA is a primary source for several basin plans: Des Moines Creek, Miller Creek, Walker Creek. High levels of PFAS (forever chemicals) have already been detected on the plateau. Ask: create an independent testing system for all main watersheds as far as Puget Sound.
#5 The build-out already done doesn’t get counted. The Third Runway and everything built since 2008 are folded into the “existing conditions” baseline — so their impact becomes the zero line instead of a harm anyone has to account for. That’s not leaving them out. That’s baking them in. And it hasn’t stopped: North Satellite Phase 1 (2019, ten new gates), the International Arrivals Facility (2022, international gates nearly doubled, arrivals capacity to 2,600 passengers/hour), the Concourse A expansion (2025, 57,500 sq ft), and the C Concourse expansion (2026, 108,000 sq ft, four new floors) all landed in the same baseline, none of them cumulatively assessed. Ask: count the Third Runway and every project built since 2008 in the cumulative analysis, not as part of the baseline, and quantify what each one added on top of everything proposed now. (More from STNI: individual vs. cumulative)
#6 Problems with existing build-out have not been evaluated. Projects such as the North Concourse have uncovered pre-existing issues with bad soil. It must be assumed that similar issues will be uncovered in other projects. Ask: surrounding cities must be allowed independent inspection.
#7 SR-509 was permitted separately. The highway work that feeds traffic and capacity to the airport was reviewed and approved separately by the state in 2003 and 2018 — long before the current DEIS. So the impacts of both, including their synergies to provide greater future capacity, are never properly accounted for. The airport and the road are one system. Reviewing them apart hides what they do together. Ask: a combined analysis should be performed that considers SR-509 and the SAMP as the single system they are — traffic, capacity, and stormwater loading on the same creeks — instead of two separate reviews.
#8 Phase 2 is being kept off the table. The Long-Term Projects — the second half of the SAMP, discussed in 2016 — were renamed a “long-term vision,” that is “unknowable beyond five years” and thus allowed to fall outside this review. Same expansion, split in two so the long term outcomes never get evaluated as a whole. Ask: study the Long-Term Projects together with these Near-Term Projects. They serve the same expansion and should be reviewed as one. (More from STNI: the construction never ends)
.#9 The Port’s own authority to limit night flights is never analyzed as an alternative. Under 14 CFR Part 161, the Port — not the FAA — holds the authority to study and potentially impose restrictions on nighttime operations. This is separate from the No Action/Action choice: No Action doesn’t slow night growth, it just doesn’t build these 31 projects, while operations keep climbing anyway on the momentum already baked into the baseline. A Part 161 restriction is the one tool that could directly constrain what happens in the 10pm–7am window, regardless of which alternative is chosen — and the DEIS never discloses whether the Port considered it, studied it, or rejected it, or why. Ask: analyze a Part 161 restriction on operations in the 10pm–7am window as a distinct alternative, independent of the Action/No-Action choice, and disclose whatever internal analysis — if any — the Port has already done on its own authority to pursue one.
.#10 The DEIS never asks whether the growth has to happen this way. The Port’s own forecasting documents that airlines have voluntarily diverted evening flights to nearby airports and brought them back the next morning — a demand-management move the Port never systematically studied. Instead, the Port treats growth as something inevitable. Ask: analyze demand-management alternatives — including an expanded Fly Quiet program for 10pm-7am hours as a genuine alternative to unmanaged growth, the same way SEPA requires any other reasonable alternative to be studied.
The Greater Good Argument
The Port portrays the project benefits wide and its impacts narrow. The airport is worth $22.5 billion “to the region” — the whole county and state — but the harms are evaluated and portrayed as close to the 2,500 acre fence line as possible.
#11 The economic case has no foundation. Appendix K, Socioeconomics, claims job and tax benefits with thin sourcing, and appears to count temporary construction jobs as permanent. It contains numerous errors of fact. Worse, it conflates both airport revenue and jobs as beneficial to nearby cities despite the fact that most of those jobs and wages do not benefit nearby cities. Ask: an independent socioeconomic study with properly sourced numbers that separates temporary construction jobs from permanent ones and shows the net effect on each neighbor city over time — not just the region. (More from STNI: Appendix K socioeconomics)
#12 The airport is a net drain on its neighbor cities. The airport pulls in uses that demand public services without paying a tax base to match — and the surrounding cities cover the difference. Growth that only pencils out for the county isn’t growth for the people living next to it. Ask: weigh the airport’s cost to adjacent cities — the public services it demands against the tax base it brings — city by city, not county-wide. (More from STNI: the cost/benefit analysis)
#13 Kids and schools. The schools under the flight path are among the lowest-performing in both King County and the State. After decades of a “regional economic engine” next door, this has only gotten worse. It’s also self-reinforcing: families who can choose where to live don’t choose the worst schools in the state, so the neighborhoods around those schools lose the residents most able to invest in them, which drags the schools down further. The DEIS asserts the projects won’t affect educational attainment. Ask: actually study the noise and air-quality effects on learning at the named schools under the flight path, and the effect school quality itself has on neighborhood desirability and reinvestment, instead of asserting there are none. (More from STNI: don’t reinvent the wheel)
Outdated standards
The DEIS relies heavily on standards the Port itself has acknowledged are insufficient, but uses those standards to avoid providing more reasonable mitigations.
#14 Noise — DNL 65 is the wrong yardstick. Current measurements average a whole day (and night) of noise impacts into a single number which will always read as “not significant.” Worse, the A-weighting measurement standard intentionally discards the low-frequency energy that makes homes shake. This undervalues the true single event energy by as much as six times. It also reduces the impacted area by 60% from the 1991 noise boundary. The forecast for night flights using projects outside the SAMP and the Port’s Century Agenda undercounts likely night flights within the 10pm–7am window — the most harmful to public health. Ask: re-evaluate the noise portion of the SAMP using the supplemental metrics option of Part 150, with special emphasis on the gap between night-time flights and their effect on sleep disturbance. (More from STNI: DNL65 for dummies · the Sleepy Time penalty)
#15 Air quality. The DEIS admits every major pollutant goes up, then says none of it crosses a significance threshold. There is no cumulative limit that adds it all together over time. “Each piece is under the line” is not the same as “the air is fine.” Ask: produce a cumulative air-quality analysis that adds the emissions up across all projects and over time against health-based limits — not a project-by-project check.
#16 Water and PFAS. Stormwater and PFAS contamination are checked against standards that were already too weak, and tested at the pipe rather than in the creeks people live near. Des Moines and Miller/Walker Creeks are already on the state’s impaired-waters list. Compliance with an inadequate standard proves nothing. Ask: monitor in the creeks themselves, not just at the discharge pipes; set an enforceable PFAS cleanup standard; and give the downstream cities a formal monitoring role in water they drink and fish. (More from STNI: the PFAS standard delayed to 2031)
#17 Fifty-year-old land-use guidance offers no way to make communities whole. Land near the airport has been steered toward airport-compatible, non-residential uses since as early as 1976 — this isn’t new. What’s never existed is an economic mechanism to compensate a city for the housing capacity that gets taken out of play when noise-compatibility standards push land out of residential use. Meanwhile, state law now requires these same cities to hit specific housing targets under the Growth Management Act — but you can’t meet a housing mandate with land you don’t have, and you can’t buy substitute capacity with tax revenue the airport has also been suppressing. Surrendering land to the airport’s footprint might be tolerable if it paid for itself. Right now it doesn’t pay for anything. Ask: require the SAMP to identify, parcel by parcel, how much residential capacity in each host and neighbor city has been removed from play by noise-compatibility standards since 1976, and require an economic offset — cash, land swap, or GMA target credit — for cities that have to plan around it.
Right of inspection
#18 Let the cities inspect the work. Given the scale of these projects, the Port’s history of cost overruns, bad soil, tree loss, and water quality litigation, and the fact that it self-permits, the surrounding cities should have the right to inspect before any ground is broken — including demolition — and at scheduled points both during and after construction. Democracy doesn’t self-correct here on its own. It needs someone with authority watching the water, the air, and the noise the way we watch drinking-water quality — not another committee that only gets to comment. (More from STNI: the IAF cost overruns and PFAS settlement)