Is the Port of Seattle Doing Enough to Mitigate Airplane Noise?


As Seattle-Tacoma International Airport turns 75 this year, it has been hard for the region’s biggest airport to get any love from the community.

In January, state legislators, local mayors, and community activists from Des Moines to Beacon Hill assailed the Port for turning its back on residents suffering from noise and air pollution caused by the rising number of jets thundering overhead.    

In particular, the Port was accused of ignoring residents’ claims that some residential noise mitigation installations funded by the Port had failed over the last 30 years. Residents, many of them elderly and low-income, claimed that window seals had broken, allowing water to enter and causing mold to spread in homes, among other damage.

Their homes were part of a Port program that has paid for new windows, doors, and ventilation improvements in 9,400 homes at a cost of more than $300 million since 1985.

The community pressure this year set the stage for a bitter fight in Olympia with a powerful Sea-Tac-area lawmaker who surprised the Port with a bill that would have mandated the Port to set aside half its annual property-tax revenue to pay for repairs of old windows and doors and other remedial actions.   

The bill, sponsored by Sen. Karen Keiser, D-SeaTac, went much farther, including mandates for the Port to restore forests, create playgrounds, install air purifiers in homes and schools, and provide “indoor greenhouses.”

Keiser will retire later this year after 29 years in the Legislature representing the 33rd District. This bill is something of a parting shot at the Port of Seattle, which she believes has always run roughshod over the airport communities, never fully compensating them for the harm it has caused.

The Seattle Port, along with ports around the state, lobbied successfully for significant changes in the bill approved on March 1. The legislation headed to the governor’s desk is now limited to a state fund to assist the Port of Seattle with home repairs.

But the Port Commission, stung by the community complaints, agreed recently to a new program that will survey homes around the airport for failed windows and other noise-reduction installations. It sets up a $6.5- million fund for a pilot program to assess homes and make needed repairs. 

The port commission was persuaded to act even though there are no good estimates about the extent of the problem. Several residents with Port-funded improvements testified at legislative hearings about leaking windows, mold, and other problems, but the Port says no homeowners had come forward previously with evidence of failures. A Des Moines councilmember who asserted he had lists of hundreds of affected homeowners never provided any names to the Port. Maria Batayola, of the Beacon Hill Council, testified residents can expect to live eight years less than average due to environmental burdens like airport emissions. 

The controversy over noise-insulation failures is not the only episode in the long drama being played out between the community and the growing airport. Nearly 51 million passengers passed through airport checkpoints last year, and officials expect the airport to exceed pre-pandemic levels this year, fueling new complaints about noisy aircraft overflights.   

The airport is scrambling to improve the main terminal and south concourse (formerly called south satellite) to improve passenger flow and add new amenities as passenger volume rises.   But plans to build a new terminal with 19 more gates have been slowed due to delays in environmental reviews, pushing back those improvements from 2027 to 2032.   

Demand is expected to double by 2050, resulting in a regional gap in service that is roughly equivalent to all the passengers served at Sea-Tac in 2019 – about 52 million passengers. 

While Sea-Tac is racing toward its ultimate capacity, the state’s search for a new commercial airport site collapsed last year. The Legislature in 2023 created a working group to research strategies to address the state’s airport needs, but Governor Jay Inslee has appointed fewer than half its members, and there is no deadline for findings. 

Attacks on the airline industry, and Sea-Tac’s part in promoting travel, continue to grow. In addition to air emissions, blamed for increasing asthma and other respiratory ailments, the airport is under fire for contributing to damaging climate change. 

King County, through its Best Starts for Kids program, recently awarded $855,000 to several community organizations, including airport environmental critics, to “build capacity to educate and organize BIPOC and immigrant/refugee communities in cities near SeaTac Airport (STA), communities under STA flight paths, and other under-served airport communities to address environmental, health and climate impacts of aircraft air and noise emissions.”

Airplane noise and emissions were not on the minds of local leaders when the military started construction of the original airport in the rural scrublands near Bow Lake during World War II.

In 1949 the Port opened the first modern terminal and a single runway for commercial use. A second runway was built in 1970, followed by a third runway in 2008, after more than 20 years of legal and political battles. 

Like the railroads of the 19th century, the airport was and remains a vital engine for the region’s economy. More than 18,000 people work at the airport. Airport activity contributes to more than $22 billion in business revenue to the region.

But as Seattle’s economy grew and jet travel took off, pressure grew to address impacts on the thousands of homes that grew up around the airport. 

In the 1980s, the Port launched its first residential noise-mitigation program, largely funded by federal aid. 

The FAA sets strict guidelines on eligibility for insulation improvements. Only structures that lie within an area defined by measured high noise exposure – the “65 DNL” standard that averages day and night noise – can get the improvements. As airliners have grown quieter, the 65 DNL area has actually shrunk over time. 

Improvements are tailor-made for each structure, based on noise analysis and building inspections, and can cost upwards of $150,000 for each dwelling. Since the program began, the Port has insulated 9,400 homes, along with several Highline Schools buildings. About 140 eligible single-family homes remain to be insulated, and recently the Commission expanded the program to condominiums, apartment buildings, and houses of worship. 

More than $300 million has been spent on noise insulation, on top of about $100 million spent to buy up 1,400 homes for the Third Runway project.

But as years have passed since the first homes were insulated, some of the installations have failed. Some failures were due to defective equipment and poor installation by a contractor many years ago. Since then, reports emerged about other breakdowns – window seals broken and leaking, allowing water in and fostering mold and damage, among other claims of damage.

The reports came to light primarily from JC Harris, a Des Moines City Council member and long-time port critic. Asked by the Port to provide names or addresses, Harris initially agreed but never did so.

The Port planned to investigate reports of failed installations in coming years as part of an upcoming airport noise study. So, the Port was surprised when Sen. Karen Keiser, Sen. Tina Orwall, and community activists announced legislation in January that would mandate the airport create a remedial mitigation fund to repair homes with failed improvements. 

In addition, the bill would have required the Port to restore urban forests, pay for air filtration in homes and schools, and provide indoor recreation space and greenhouses. A state noise-mitigation fund also would have been created.

The bill would have required the Port to devote half its annual property tax levy in 2024 to pay for those improvements, plus one percent in future years.

That bill was dropped without any forewarning to the Port, where it was viewed as an unprecedented intrusion into the Port’s prerogatives about use of its tax dollars, as well as saddling the Port with mandates far outside its authority.

Keiser said the legislation was necessary to remedy years of neglect by the Port. “The closer you are to the airport, the lower your life expectancy,” she said at a press conference, and the state should step in to help “repair these incredibly awful conditions.”   She estimated 200 or more older homes need repairs. 

For years past, in the competition for limited money, the Port said buildings that had never gotten insulation should get priority over homes that had been improved years before. 

Commissioner Sam Cho was angry that Keiser had kept the bill a secret from port commissioners. The legislation “tries to pre-empt the port by telling us how to spend our tax levy,” he said. “It’s not as if we aren’t doing everything we can to make it more equitable.”

At a later Port Commission meeting, Cho continued to criticize the bill. “I think there are some leaders who are disingenuous about the topic when they insinuate the Port is not doing its part on sound insulation,” he said.

The bill was significantly revised under pressure from the Port and the state’s port association. More modest substitute legislation, setting up a state program to assist local homeowners with a $5 million appropriation, was approved by the Legislature on March 1. 

Even so, the Commission was stung by the community complaints that underrepresented communities around the airport were being ignored. 

As Keiser’s bill was nearing passage, Commissioner Hamdi Mohamed introduced an order creating a special program that would speed up investigation of airport-area homes for failed improvements. The commission set aside $6.5 million in Port property- tax money to complete the survey and construction planning by 2025. 

“It is putting action into being the best neighbors we can be,” said Mohamed, herself a South King County resident.

Keiser complimented the Commission for the action.   “The Port of Seattle attitude has really been a total change,” she said.

Community members applauded Mohamed and the Commission for the action, which they clearly viewed as just a first step in a much wider effort for the Port to address noise and air emission impacts throughout the region, not just around Sea-Tac.

“Think of this as start-up capital,” said Harris, the Des Moines councilmember.

The Commission unanimously approved Mohamed’s order, but with scant discussion of key details about how many homes are eligible, how the home surveys will take place, the criteria for evaluating cases of failure, and criteria for determining what repairs are justified.   That work still lies ahead.

But as an example, at an average cost of $150,000 per new installation, the cost to repair 200 homes could be upwards of $30 million. Some homes might need less than full replacement, however.

Federal law historically has barred use of FAA money for failed noise improvements. Sen. Patty Murray, however, secured $3 million to assess the condition of noise insulation in older Sea-Tac area homes in the Transportation Appropriations bill approved Friday. It goes to the president for signature. “Sen. Murray has truly championed the issue of noise insulation in homes near SEA,” Mohamed said.

The commissioners’ action was a break from former Port policy and shows an increasing willingness to use local property- tax funds for community programs that formerly were federal prerogatives. San Francisco International is the only other airport in the country that is exploring repairs of old installations, an effort dogged by high costs and other delays.

In any case, the commission action likely will disappoint many people who live under flight paths but are distant from the airfield.   

The Port effort will be limited only to those homes with failing port-funded improvements within the narrow 65-DNL noise bubble around the airport. It will only address noise levels only— – not air emissions, respiratory ailments, or any other impacts. 

Those battles will surely come when (or if) the airport comes forward with its plan to add more capacity by building a terminal with 19 new gates.   

In the past for the most part, the Port has only had to contend largely only with close-in communities, which depend heavily on the airport for their livelihoods.   

The latest debate makes it clear the issues are turning increasingly to claims of disproportionate impacts on communities of color throughout south King County north to Beacon Hill.   Of course, Sea-Tac is not the only culprit—highways, railroads, and Boeing Field generate huge emissions. 

As it tries to expand, the Port can expect tough questioning not only from airport neighbors but also from an increasingly well-organized coalition of environmental groups and community groups ranging far from the airport. 

Mike Merritt
Mike Merritt
Mike Merritt is a former writer and editor for local newspapers. He recently retired as senior executive policy advisor for the Port of Seattle.


  1. What about the siren noise in downtown Seattle?? It sounds like a city under attack all day long. That’s something the mayor and city council can do something about.

  2. Hi Mike,
    Thank you so much for posting your well-informed story on our legislation, SB 5955, to begin the long process of addressing airport community concerns. I just posted it on my Facebook page. You might also want to know that we were also able to access several million dollars in Climate Commitment Act (CCA) funds to address airport community air pollution concerns. With the UW Department of Health and Occupational Safety’s survey detailing the threat of “ultra-fine” particulates from jet engines to our constituents, Rep. Tina Orwall and I have been working to get classroom air purifiers with HEPA filters in our public schools and other community settings. These classroom air filters are more effective than HVAC at removing ultra-fine particulates, although it’s still a problem outside the classroom. The Highline School District has already purchased classroom air purifiers using COVID funds for many of its elementary schools. Thanks again for your reporting!
    Senator Karen Keiser


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