King County will begin capping trails in Maury Island Natural Area later this month (Courtesy Photo).

King County will begin capping trails in Maury Island Natural Area later this month (Courtesy Photo).

County to begin cleanup of polluted Maury park

Contractor bid evaluation process underway; some trails will be temporarily closed to public.

King County Parks is preparing to launch the first phase of a multi-million dollar, 10-year cleanup of Maury Island Natural Area this month, reversing decades of industrial contamination from Glacier Northwest’s mining operation and the Asarco copper smelter in neighboring Ruston.

Before it was decommissioned in 1986, the smelter released a toxic cocktail of heavy metals into the environment that later settled into the topsoil across the Puget Sound region, including much of this island, posing health risks today.

Consisting of a patchwork of different parcels, not all of the natural area will receive the same treatment, such as the mountain bike trails in Dockton Forest, which were not included in an agreed order for remediation work between the Washington Department of Ecology and the county.

Cleanup plan

The cleanup action plan includes capping trails and the former skeet shooting range, which will be transformed into a gravel parking lot that will be able to accommodate 20 vehicles and four equestrian trailers. The county will also perform invasive vegetation removal for 5 acres of property next year, and at the request of the public, herbicides will not be used to control regrowth.

All of the work in Phase One is made possible by a Washington State Department of Commerce Grant for $2 million.

The cleanup process comes years after islanders, activists and the county took up the fight against the planned expansion of Glacier’s sand and gravel mine on Maury Island. After that effort to expand was defeated, in 2010, the county purchased the expansive, 275-acre property using a combination of funding sources. But all along, the county’s cleanup plan has had its doubters.

A series of public meetings hosted on Vashon by county officials and the state in the following years were met with mixed reactions, with many questioning why it was necessary to intervene at all, opting to let the site return to wild nature and keep it as it was.

Some of the conditions the county set for use of the natural area did not win broad popular support. Recreational activities that were previously unrestricted, such as dirt biking, were prohibited because they were thought to cause degradation. Scuba divers were put on notice that they could no longer tie their boats up to the creosote pilings of the old pier, which the state took down in 2016.

Away from the tidelands, more than two dozen well-traveled hiking trails weave through the madrone forests of the natural area. There, the county will lay down 3 to 4 inches of gravel and another 3 inches of compacted soil on top of that to eliminate the chance of exposure to deposits of arsenic and lead.


The state Model Toxics Control Act (MTCA) sets a threshold for the presence of heavy metals in soil — that limit is far below what has been measured in the natural area. The county found 20 times more arsenic at the natural area than permissible under the MTCA and more than three times as much lead.

Long-term exposure to levels as high as what was found at the property could potentially cause cancer, said project manager Lindsey Miller.

“As long as people are using common sense in how they interact with the [land], they should be fine,” she added.

All of the trails are open for shared use, including for mountain bikers and equestrians. Miller said the addition of compacted soil is partly for them, as horses and bicycles do not fare well on gravel. It also amounts to an extra layer of protection for user groups, despite coming at a higher cost for the county to maintain. Parks will have to monitor the trails quarterly throughout the year and report back to the Department of Ecology with their findings, said Miller.

She added that the inhalation of dust kicked up from soil is not the primary pathway of exposure to the contamination, but Marian Abbett, project manager of the Department of Ecology’s Tacoma Smelter Plume Project, said that it is still worrisome.

The pervasiveness of the contamination, she said, means that even microscopic particles of arsenic and lead can accumulate in mucus in the respiratory system, eventually leading to ingestion, the primary pathway of exposure.

“We are concerned about dust exposure,” she said.

In Dockton Forest, the Vashon Mountain Bike Association organizes monthly volunteer work parties to maintain riding trails first created in 2017 by the county and Evergreen Mountain Biking Alliance. Volunteers were out as recently as last Saturday, according to Brian Starr, owner of Vashon Bikes in town, smoothing out the bumps and dips where needed.

Abbett said the conditions are likely safe enough for them, as the volunteers have continually chiseled away at the surface layers where the arsenic and lead settled.

“Contamination tends to stay in that upper layer of soil,” she said. “But sampling is the only certain way to know what’s been left behind.”

But Cheryl Ann Bishop, a spokesperson for the Toxics Cleanup program at the Department of Ecology, said the trails at Dockton Forest have not been sampled. The state expects that arsenic and lead levels will remain consistent over time unless the soil has been disturbed.

She added that the Department of Ecology has focused its sampling to residential yards and play areas at schools, daycares, parks and camps.

“We have not had a focus on sampling along dirt bike/horse trails,” she wrote in an email.

Island input

Many of the decisions guiding the county’s stewardship of the natural area were shaped by user groups such as the Friends of Maury Parks, who gave input about a range of subjects from preserving view corridors to the development of a fire management plan.

Three years ago, Vashon Adventures and King County Parks debuted the first campsites at Maury Island Marine Park — the natural area’s sister park, separated by the neighborhood of Gold Beach. The campsites have been available by reservation since, open between May and October. Pack in and pack out by foot, bike or kayak — there is no running water and fire is strictly prohibited.

Islander Michael Sperazza lives nearby and said he was concerned that there would be no warning if a pernicious campfire started to burn out of control, so he began attending meetings hosted by the Friends. A member of the island emergency operations center, Sperazza recently coordinated citizen patrols across the eastern side of Maury Island this Fourth of July to watch for wildfires.

His endeavor, said Adam Atwell, who belongs to the Friends, is an example of the deep involvement islanders have had in the process of creating what the natural area is today.

Acting as liaisons of sorts, Atwell said the Friends were privy to conversations about parking as well as general progress. He also said the Friends played a role behind the county’s decision to move a number of trees first planted in the natural area to the marine park earlier this year, ensuring the view of the Olympic Mountains is not obstructed.

“Our group actually did provide good input that helped inform the final plans in a way that won’t be as unpalatable to the community,” he said, lauding King County Parks for being transparent and for reaching out. “It’s good for them, too. They want to know what the community wants.”

One comment the county heard from islanders is that all of the trails in the natural area should remain open. Based on that feedback, the county decided not to close any of them for the time being, electing to cap the trails with contaminate levels exceeding cleanup thresholds. Some do not have contaminant levels over the thresholds that trigger a cleanup action and will not need to be capped.

“What we hear most about from the public in that site is accessibility. People who live on the island and are accustomed to using the old quarry site, they just want to make sure the access is maintained and that they can continue to use it,” said Cris Matthews, the natural area site manager for the Department of Ecology.

Still, he emphasized that the general public should stay on the marked trails when the cleanup is finished, recommending that all users of the natural area use their best judgment.

Public Health Seattle & King County and the Department of Ecology have advised for some time that all residents living within the smelter plume regularly wash their hands, clean pet paws before animals come into the house and take off shoes before walking through the door. Officials from the Department of Ecology will be at the Vashon Farmers Market this Saturday to offer free soil sampling to detect arsenic and lead levels. More information is available online.

The Friends of Maury Parks are looking for additional volunteers who are interested in the final planning and operation of the Maury Island Natural Area cleanup. For more information, email Adam Atwell at

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