SOUTH PARK — Trenton Nolan was walking Oly, his white shepherd, through the neighborhood earlier this month when he was hit by a strong smell of sulfur. His dog started sneezing, and he raised his hoodie over his face and rushed to get away.
His partner, Jennifer Scarlett, said the same smell had seeped into their nearby home and given her a headache at least three or four times in the past month and a half.
“The word that jumped into my head was ‘caustic,’ ” Nolan said. “I was like, ‘Wow, this is really acrid and alarming, like I feel like I’m in danger here.’ ”
The two were not alone. Between Sept. 19 and Nov. 7, the Puget Sound Clean Air Agency received over 110 reports from about 80 residents and workers across South Park who described smells of sulfur, rotten egg, feces or natural gas. An agency inspector in the neighborhood confirmed a sulfur smell at least four times, according to PSCAA records.
Residents have described instances of the smell lingering in their homes, causing headaches, itchy eyes and runny noses and making it difficult to breathe. Records and interviews indicate the smell was not persistent throughout the day, or over days, and has varied in intensity.
The source of the smell had been a bit of a neighborhood mystery. But the PSCAA inspector zeroed in on a facility that has recycled drywall. The company, Gypsum to Gypsum, had been removing a large, years-old pile of crushed gypsum as it worked to vacate the property. Complaints filed to PSCAA and people interviewed also said they believe the drywall facility to be the source.
Company representatives did not respond to requests for comment about its facility. During a visit to the site, a worker, who identified himself as a general manager for the company but declined to give his full name, told The Seattle Times he didn’t notice anything out of the ordinary during the time of the reports, but acknowledged that old drywall gives off a little sulfur smell.
The PSCAA inspector identified the smell as hydrogen sulfide, a highly toxic, colorless gas that emits a strong rotten-egg odor and can be detected by humans at low concentrations. At low levels, it can cause eye, nose and throat irritation, while moderate levels can lead to headaches, nausea, coughing and difficulty breathing, according to the Agency for Toxic Substances and Disease Registry. High levels can cause shock, convulsions, coma and death.
PSCAA, the regional clean air authority responsible for regulating emissions affecting air quality, public health and climate change, can issue penalties for odors if they meet a certain legal threshold.
Citing the ongoing investigation, the agency declined to be interviewed about the smell, its source or anything known about the gas’s concentration in the neighborhood.
Agency spokesperson Phyllis McElroy said in a Nov. 6 email, “The issue is on our radar and is being taken seriously.”
Natural gas can also have a sulfur smell because of additives that make it easier for humans to detect; however, utility Puget Sound Energy said in early November that no leaks from its systems in the neighborhood had been detected, despite some calls reporting odors.
A spokesperson with Seattle Public Utilities, which manages some sewer and water systems in the neighborhood, said that while their staff have reported odors coming from the drywall recycler and staff have investigated, it is unable to “confirm the source of the odor with certainty.”
Seattle City Councilmember Rob Saka, in an emailed statement Nov. 19, said the situation was “totally unacceptable” and his office had reached out to city departments to confirm PSCAA was responding. Saka said a source of the gas had not yet been identified.
“This neighborhood demands heightened attention, urgency, and resources from all levels of government,” Saka wrote, given the generations of environmental harm and disproportionate impacts from industrial activities.
The smell hasn’t been reported since Nov. 7, but members of the Duwamish River Community Coalition, an environmental justice group, say they have been frustrated by the lack of communication and response from PSCAA.
The Duwamish Valley is flanked by highways and heavy industry, and is plagued by flooding made worse by climate change and sewage overflows. It is also under a flight path where pollutants are in higher concentrations, and along one of the nation’s most polluted rivers. Yet residents say they have never experienced such a pungent, disruptive smell before.
Paulina López, the executive director of the community coalition, said that despite working closely with PSCAA, including being on their advisory council, the agency does not meaningfully protect public health and lower air pollution.
“The DRCC [doesn’t] have a way to say that (PSCAA) is actually an agency that will protect the community,” she said. “They’re not responsive. They take their time.”
Looking for a source
Residents first reported the sulfur smell to PSCAA on Sept. 19.
Sierra Stoughton said that when the smell showed up in their home in early September, she and her husband began searching for a cause. Only when they stepped outside did they realize how widespread it was.
It would follow them for weeks.
“I would smell it — if it was on a walk, I would turn away. If it was in my car, I’d keep driving and hope it wasn’t at my house. If it was in my house, we’d leave,” Stoughton said, who worried about how it might affect her pregnancy.
Between Sept. 22 and Nov. 5, PSCAA sent an inspector to South Park five times and confirmed the smell of hydrogen sulfide four times, often driving and walking around the neighborhood to locations where the smell had been reported.
Investigations related to odor complaints are separate from those related to risks to human health.
These surveys, which typically rely on the inspectors’ noses, identified odors that were “barely detected” and “distinct and definite” with recognizable “unpleasant characteristics.”
To rise to the level of a nuisance violation — or an odor that “unreasonably interferes with enjoyment of life” — the agency weighs the duration of the odor and the ability to identify a source.
According to PSCAA, the odors detected by the inspector were not a risk to human health.
The inspector reached out to some residents — and to King County to ensure there was not a sewage issue.
Inspectors at the clean air agency are primarily tasked with inspecting regulated sources across the counties, and odor complaints are only a portion of their work. About 2,000 to 3,000 general complaints come into the agency each year. Unless the complainant is specifically asking for an update they might not hear about the outcome of the investigation.
Between Nov. 3 and 7, around 65 complaints about the smell were filed with PSCAA. López said the stench was especially bad around this time.
The agency inspector reports and interviews with residents pointed toward Gypsum to Gypsum at 816 S. Kenyon St.
Residents said a pile of gypsum, used to make drywall, stood a story tall outside its facility.
SPU says it bought the property in 2024 and Gypsum to Gypsum had until Nov. 25 to vacate. Duwamish River Community Coalition leaders described excavators on site clearing the gypsum pile, which was hauled out on trucks.
A PSCAA inspector wrote in an Oct. 13 report that after driving with their windows down around the neighborhood, they were able to pick up the smell of hydrogen sulfide outside the company’s vehicle entrance.
The inspector noted at one location that it was 75 feet from the company’s “exposed gypsum pile” and it appeared about half the pile had been removed, before continuing to drive in the neighborhood.
“At that point it seemed probable that the hydrogen sulfide odor was coming from” the facility, the inspector wrote.
The inspector wrote they also discussed “the odor complaints and my opinion that the odors were coming from their exposed gypsum pile” with the facility’s manager, who said he and his employees have noticed a “rotten egg” smell and the intensity “varied as various sections of the pile were exposed.”
The inspector wrote they were able to confirm the pile was the source of the smell.
By Nov. 5 an inspector noted the height of the pile was down to 6 feet. During the survey, the inspector spoke with an SPU employee working on the floodwall at the river’s edge who said they had experienced the odor “regularly” and that it had been “real bad” that morning.
As of last week, the pile had been removed.
Community concerns
Scarlett said that when she first smelled the odor, it was worse and different from when she was outside planting tulip bulbs and her neighbor, also gardening, put a shovel through a natural gas line.
“It’s strong enough to wake you up from completely being asleep, and you just feel like you can’t breathe. It gives you an instant headache,” she said.
The smell had not been felt evenly across the neighborhood.
DRCC community engagement and communications specialist Maggie Angel, who lives across the street from the drywall recycler, said she had not noticed the smell being particularly strong and had not always smelled it when others on social media had reported it.
Robin Schwartz, who also works at the Duwamish River Community Coalition and lives nearby, said she had not noticed the smell much, though her daughter once complained of an egg smell inside the home in early November.
Public health in South Park because of exposure to pollution has long been a concern for residents.
The state’s Department of Ecology considers the area along the Duwamish River, including Sodo, South Park and parts of Beacon Hill, Tukwila and SeaTac, as one of the state’s 16 “overburdened communities highly impacted by air pollution.”
An Environmental Protection Agency-funded study found that South Park and Georgetown residents tend to live eight years shorter on average compared with Seattle and King County residents. The same study found that children in the Duwamish Valley have among the highest rates of hospitalization due to asthma than any other neighborhood in the city.
Evidence supports air pollution as a cause or is associated with heart disease, preterm birth, dementia, cancers and other respiratory conditions, said Anjum Hajat, a social and environmental epidemiologist at the University of Washington who has worked with communities in the Duwamish Valley to reduce indoor air pollution.
When the smell was first reported, the Lower Duwamish Waterway Group, representing the city, county and Boeing in the river’s long-term cleanup, reported there was no evidence the smell was related to the ongoing dredging of the river. A King County spokesperson said hydrogen sulfide is monitored at the dredging site and they shared the odor complaints with PSCAA.
In the last month, the Duwamish River Community Coalition shared updates for residents through social media and newsletters and encouraged residents to report it.
López said residents have been left wondering whether the air is safe to breathe.
While the smell may be gone, the community coalition’s environmental health equity manager Joseph Santana said the response from the agency follows the trend of the community’s public health concerns not being taken seriously.
“I feel like this will happen again with some other smell,” he said.
