Seattle’s Gas Works Park sits atop a toxic legacy, cleanup is still years away
Sep 8, 2026, 9:06 AM
(Photo courtesy of KIRO 7)
(Photo courtesy of KIRO 7)
This summer at Gas Works Park, a new sound to Lake Union has brought a fresh conversation to a decades-old problem: contamination from the land’s past life as a coal-oil plant.
On the surface, Erik Hillesheim has brought “Paddle Board Raves” to the Seattle lake. At each event, a collection of people on various inflatable water gear come together for a music performance from the back of a boat.
“This feels so quintessentially PNW, right?” Hillesheim said, “We love having our concerts in front of this iconic view of the city.”
The concerts started by word of mouth on social media, growing quickly by the end of last summer.
In hopes of reviving it with a larger, more consistent schedule, Hillesheim and his organization, Seattle Paddle Raves, sought a special use permit from the city. That permit came with a surprise requirement — don’t let anyone enter the water at Gas Works Park and create a plan for them to enter at other areas of the lake.
“There’s no issues at the top of the water; it’s more in the sediment as we understand it,” Hillesheim said.
So, what exactly is the issue? Contamination that remains from when the coal-oil plant last shut down in the 1950s. It’s an issue that literally bubbled to the surface in the early days of the park on a sunny day in 1984 when a man called the Environmental Protection Agency (EPA).
“He said he saw tar bubbling up from the ground and he saw oily sheens at the shoreline,” Amber Wong said, who retired from the EPA after overseeing Gas Works Park and the agency’s Superfund program for decades.
The call inspired sampling of the ground and the water. A few days after the report, then-Seattle Mayor Charles Royer closed the park. The image of people in white Tyvek suits made the airwaves of KIRO 7 News and several newspapers that spring.
Divers from the EPA checked what was under the surface.
“There were oily globs, some of them were sort of fist-size, sort of globular.” Wong said, “When you would wave your hand over them, they’d kind of undulate.”
The EPA created a report, handed it over to the city, and nothing happened for ten years.
In Wong’s World, the EPA’s Superfund program was starting to get going as the 1990s did — identifying the most contaminated places in the United States and creating a thorough approach to clean them up. Wong wanted Gas Works to make that list.
“It’s hard to have a site where you know it’s contaminated, and there are releases to the environment, and nothing is happening,” Wong said.
Just as the plan was ready to go — the federal government shut down in 1995, halting her work. After a reopen and shutdown and reopen again in 1996, the Superfund program moved forward with a twist — a site could only be cleaned up if the state’s governor signed off on the project. Wong says then-Governor Michael Lowry didn’t ink the paperwork.
“People are afraid of problems, and if they’re afraid that we’re going to unearth a problem, they just didn’t like that,” Wong said.
“Really what the governor wants to say is, ‘oh yes, there’s a very big hazardous waste site, and it’s here and the government, the federal government has to come in and take care of it,’” Wong continued.
Wong handed the plan over to the Washington State Department of Ecology who has been testing the water again and again and again since the 2000s.
Kim Wooten, who is Ecology’s Toxics Cleanup Program Regional Section Manager, said the delay in a cleanup is because of changing conditions under the surface the litany of tests have uncovered. The tests, Wooten said, ensure that the cleanup will only need to happen once.
“There have been, compared to some other sites, a ridiculously large number of samples taken at Gasworks to really understand what’s going on, and so those investigations take quite a while, but it gets us to a really good cleanup at the end,” Wooten said.
There are some areas of remediation on the land portion of the park Ecology. Wooten said it is essentially pushing any contaminants further beneath the surface. That cleanup will take place this fall, but the cleanup of the water is still years away.
Wooten said tests are mostly complete in order for the department to submit its permit application with the federal government. While Wooten said there are not the oily blobs that the EPA saw in the 80s, the focus is on digging up contaminants at Lake Union’s shore and covering the sediment under the water near the park.
“It’s slowly naturally getting covered, so less and less every year is exposed,” Wooten told KIRO 7.
“In some areas, they’re just going to add kind of clean sediment on top to make sure we have enough of that depth for those organisms that live in the sediment,” she continued.
The cleanup will cost about $73 million. For Hillesheim, he’s excited for the cleanup and has enjoyed teaching other people about it.
“It’s been a cool opportunity for both us to educate as well as to be able to continue to throw our on the water concert series,” he said.
While he’s happy the City of Seattle allows the series to happen, he is hoping there is a solution to bridge the years before cleanup.
“Maybe there’s some sort of floating dock or element that you could actually use the space today, even in lieu of not being able to do the whole cleanup in the next few years,” Hillesheim said.
