The Port of Seattle is taking the next critical steps toward what will be Seattle-Tacoma International Airport’s last major expansion before it runs out of room.
On Oct. 31, the Port published the federal environmental assessment of its Sustainable Airport Master Plan (SAMP), which analyzes the impacts and potential mitigation for the master plan. The public has until Dec. 13 to comment on the massive report.
The SAMP has 31 separate “near-term’’ airfield, roadway and passenger projects. The largest and most controversial element is a new passenger terminal with 19 airplane gates to be built north of the existing terminal, along with new parking and expanded air-cargo space. Today the airport has 89 gates.
Sea-Tac is in a race against time to finish expansion projects to accommodate air-travel growth that shows no sign of abating. After a pause during the pandemic, Sea-Tac recorded 50.8 million passengers in 2023, just shy of the record set in 2019 before the pandemic.
Based on what the Port can afford and squeeze into its small footprint, the proposed expansion would handle 56 million passengers with reasonable efficiency in 2032, when the projects would be completed. Even that number will likely fall short of actual demand, the Port forecasts.
But before ground can be broken, the airport will likely face legal, financial and political challenges as big as any since the battle over building a third runway in the 1990s. Nearby communities will likely fight the expansion and demand compensation for impacts, while business leaders say the airport is vital to sustaining the region’s economic health.
The 2018 cost estimate of all 31 projects was $5.6 billion, but construction costs have risen sharply since then and the actual price tag could be double that figure or more.
After slowing during the COVID pandemic, travel activity returned to steady growth due to Puget Sound’s “young, diverse and affluent’’ population, Airport Director Lance Lyttle told the Port Commission recently. “These are all the ingredients that drive the demand for travel. We (the Port) don’t control the demand,’’ he said.
Airlines that serve Sea-Tac are clamoring for better passenger and aircraft facilities, driving the airport to spend $1 billion a year on ticketing, checkpoint and retail upgrades within the existing terminal. None of those projects add capacity to meet future demand.
The airport’s biggest customer, Alaska Airlines, is now a member of the global One World Alliance and is in the process of acquiring Hawaiian Airlines, which flies to several Asian cities. Delta Airlines, Number 2 at Sea-Tac but the largest U.S. airline, has made Seattle its hub for Asian destinations.
Rachel Smith, CEO of the Metropolitan Chamber of Commerce, said the upcoming World Cup soccer matches, expansion of the state convention center, and Alaska cruise growth all point to the need for more airport capacity.
“This region is too big and economically vibrant for the status quo at Sea-Tac,’’ she said.
The SAMP plan was unveiled in 2018, starting six years of environmental review by the Port under federal review. The pandemic and other delays slowed the work so long that some work became outdated and had to be redone.
The Port says the projects will address five major shortcomings at Sea-Tac:
- Shortage of space for passenger ticketing, parking, roadways, security facilities and aircraft gates
- Cramped air-cargo facilities, which need more aircraft parking and warehouse space
- Portions of the airfield no longer meet current FAA airport design standards
- Inadequate taxiway layout
- Jet fuel storage should be doubled to meet projected demand and the Port’s Sustainable Aviation Fuels initiative, which aims to supply at least 10 percent of airlines’ needs with non-fossil renewable fuel
All the projects are within the airport boundary, except for one port-owned parcel north of Highway 518.
The report analyzed alternatives to airport expansion, such as high-speed rail and mass transit. It also considered proposals to limit growth, close a runway or shift airplanes to other airports. None would meet the region’s future air-travel needs, and the airport has no authority to turn away aircraft or mandate they use other airports, the assessment concluded.
A potential alternative to the proposed north passenger concourse is to build new passenger facilities connecting to the existing Concourse D.
The 31 proposed projects serving 56 million passengers in 2032 were developed based on the Port’s financial capacity, the limited area of the airport, and constraints in the crowded airspace shared by Sea-Tac, Boeing Field and Renton airports, along with Paine Field and other smaller facilities.
Airport projects are funded through a combination of passenger fees, airline revenue, federal grants and non-aeronautical income from parking, food and beverage sales.
But the Port admits that even the target of 56 million passengers likely falls short of actual demand, which may reach 58.3 million passengers in 2032. Airspace and airfield limits will lead to congestion and delays for airlines and passengers, the studies show.
The assessment of environmental impacts is likely to draw criticism from opponents for understating health and climate-change effects.
The assessment found “less than significant impacts” on air pollution, environmental justice, climate and noise resulting from proposed terminal and airfield improvements. The only category which registered significant impacts requiring mitigation was traffic congestion caused by more vehicles on local streets.
These findings may be surprising given the often-repeated claims that airport noise and air emissions are causing illnesses and shortening the lives of near-airport residents.
A December 2020 Seattle-King County Public Health report to the Legislature found “pervasive health concerns” among residents near the airport. The study cited higher rates of premature and low-birthweight pregnancies, respiratory ailments, heart disease and other illnesses, which the report linked to airport emissions.
Critics also point to the climate-changing effects of aircraft exhaust gases.
The results can be explained by the way the federal government defines impacts. According to the assessment, the impacts of doing nothing – building no improvements – are nearly the same as the proposed project plan. The reason is that airlines will continue to fly in and out of Sea-Tac at much the same levels, even without any improvements.
To push more people through the airport, airlines could use bigger planes and expand flights over more hours of the day. Ticket prices could rise.
Based on current criteria, the region will still meet all local and federal air-quality and noise standards even with more flights. The airport disputes claims that jet emissions are to blame for the reported health problems, pointing to a myriad of other sources of pollution.
But without a new terminal, roadway and airfield improvements, the impact on the millions of airport travelers would be severe, the Port says. The level of service will decline as congestion and flight delays continue to grow.
The airport, under federal law, cannot turn away aircraft. “The airlines are going to do what they are going to do, and continue to grow,” said Commissioner Sam Cho. “There is a huge misconception that the Port fuels growth.’’
Among major American airports, Sea-Tac is lagging in planning to meet future demand. The big U.S airports, including Los Angeles, San Francisco, Chicago, Newark, Houston, Dallas-Ft. Worth and New York, all are moving ahead on ambitious plans to add gates and upgrade terminals. Atlanta’s Hartfield-Jackson airport, the nation’s busiest, is adding a sixth runway along with a host of terminal upgrades.
For many Sea-Tac Airport-area residents and public officials, a major new expansion rekindles memories of the battle to build a third runway in the 1990s.
The Port’s 1992 decision to build a third runway touched off years of political and legal conflicts. Extending the plateau westward to accommodate the runway required some 17 million cubic yards of fill, re-routing streams and creating new wetlands. About 400 homes were demolished to make way for the project, and hundreds more homes received sound insulation.
Although Des Moines, Burien and Normandy Park spent millions in tax dollars to fight the project, the City of SeaTac stayed out of the fray. The city and Port had signed a long-term agreement, still in place today, that guaranteed a steady stream of money from parking and other sources to city coffers.
The city also benefits from millions of dollars in airport retail and construction sales taxes, as well as revenue from International Boulevard hotels and rental cars. “We want to support the Port, and protect our own interests,” said Interim City Manager Kyle Moore.
The third runway was completed in 2008, 20 years after the initial studies and, at about $1 billion, twice the original cost estimate.
With the SAMP project looming, SeaTac, Normandy Park, Des Moines and Burien have banded together to hire their own experts to review the Port’s environmental documents.
Des Moines Mayor Traci Buxton said neighboring communities likely will insist the Port carry out a more extensive federal environmental impact statement, which would add months to the process.
The cities will also revive their demands that the Port do more to compensate nearby communities for the noise and air-pollution impacts of airport operations. “It will be appropriate to compensate us, recognizing that we take the impacts for the economic benefit of the entire region,’’ she said.
The Port has committed $14 million over five years for matching grants to community programs and is investing in research on cleaner jet fuel and other environmental initiatives. Buxton says those efforts fall short of the need. She said the Port should make direct grants to the cities for economic development and to compensate for air and noise impacts.
The Port has been using its countywide property tax levy to fund the growing expenditures on community programs, as federal law generally prohibits use of airport revenue for non-aviation uses. But the property tax is limited, and tapping the levy for a significant expansion of community programs would mean less money to fund port maritime and economic development projects.
“We have a lot of need for mitigation from existing flights,” said State Rep. Tina Orwall, D-Burien. Last session she won legislative approval for state funds to help replace failing noise-insulating windows and doors installed in nearby homes decades ago by the port. Going forward, the state may help fund future mitigation, but no decisions have been made on what form that assistance might take.
Brian Davis, a member of the Burien Airport Committee, believes some form of expansion is inevitable given the significance of the airport to the region.
“The airport is too important to the economy of the region, and this gives them a great deal of economic and political clout,’’ he said.
But the Port and state should ‘’recognize the sacrifice of the community members’’ and pay for greatly expanded sound and air-quality mitigation, and compensate cities for property tax revenues lost due to airport impacts. There have been no definitive studies linking the airport itself to depressed property values, however.
Smith, the Seattle Chamber head, acknowledges more community assistance may be justified beyond the narrow confines of federal law. “I do believe it’s not a zero-sum game. Mitigation is changing across the country. These questions can be looked at a little differently,’’ said Smith.
Two years or more may pass before the Port Commission is ready to take action on any of the SAMP projects. Commissioner will have to grapple with questions about how much of SAMP the airport can afford, and what airlines will pay. Alaska, as the biggest customer, will pay the lion’s share.
Meanwhile, the region inches closer to running out of airport capacity with no good solutions in sight.
The Puget Sound Regional Council’s 2021 Aviation Baseline study concluded that demand for take-offs and landings in the region will double by 2050, resulting in a regional gap in service roughly equivalent to all the passengers served at Sea-Tac in 2019. That study forecasts a need for three new runways to accommodate future flights.
A state panel created to identify sites for a new commercial-service airport ran into fierce community opposition, closing down in 2023 without any recommendations. The Legislature then formed a second committee, the Commercial Aviation Work Group, but with the limited goals of forecasting the state’s aviation needs and potential options to meet that demand. The work group has no deadlines, is still short of several key members, and met just twice this year.
The Port and community members of a community airport advisory committee are worried about the slow pace of progress. They are asking the Legislature to require the working group to “make tangible progress toward identifying additional regional airport capacity in the next three years,’’ and set deadlines “to identify and achieve clear, substantive, recommendations for action.”
