Site Description
Terminal 117 (T-117), formerly known as the Malarkey Asphalt Plant, located at 8700 Dallas Avenue South on the west side of the Duwamish River in South Park. The site is adjacent to the Boeing Company South Park facility, the South Park Marina, and several South Park residences.
The site is currently a habitat restoration site and community park know as Duwamish River People’s Park.
Site History
From 1937 to approximately 1999, the Duwamish Manufacturing Company (1937-1978) and Malarkey Asphalt Company (1978-1999) operated at the site. These companies heavily polluted the soil and shoreline of the site and went out of business in 1993. The Port acquired a portion of the property in 1999 with the plan to build a maritime cargo terminal.
In 2003, the US Environmental Protection Agency (EPA) designated the site as a highly toxic “Early Action” area with the Lower Duwamish Waterway (LDW) Superfund site. The EPA found contaminated soil, asphalt, oil, pipelines, a non-leaking underground diesel storage tank, drums and debris in the riverbank resulting in risks of exposures to polychlorinated biphenyls (PCBs), highly toxic chemicals hazardous to public health that were banned in the 1970s. PCBs were also found in the adjacent neighborhood streets and yards.
Contamination Issue
Past operations led to soil, sediment and groundwater contamination. The primary contamination of concern was PCBs.
Why Did the Port do this Cleanup?
As the current property owner, the Port was partly responsible for addressing contamination at the site. T-117 was cleaned up as a joint project of the Port and the City of Seattle with oversight by the EPA. After the cleanup, the Port converted 14 acres to critical fish and wildlife habitat and public shoreline access. This large-scale restoration project supports recovery of the endangered Southern Resident orca population by significantly increasing habitat critical to abundance and health of Chinook salmon.
Status
Phase I of the T-117 cleanup – addressing upland soils and in-water sediments –was completed in December 2014. The Phase I cleanup included removal of pavement, derelict structures, and 60,000 tons of soil and sediment. PCB contaminated soil and sediments were excavated and hauled off-site to a licensed waste landfill. The City of Seattle began Phase II of the environmental cleanup in 2015, including stormwater and street right-of-way improvements in upland areas adjacent to T-117. During construction, steel sheet piling was used to isolate contaminated soil and water from the river.
The Port and the City of Seattle are continuing to monitor the effectiveness of the cleanup and to ensure that it is still protecting people and the environment. As of 2025, year 10 monitoring was completed and demonstrated that the remedy is still effective. The site will continue to be monitored as part of the larger Lower Duwamish Waterway Cleanup.
In 2020, the Port broke ground on the construction of Duwamish River People's Park, a habitat restoration site and community park that opened in 2022.
Contact Information
Joanna Florer | Senior Manager, Environmental Programs | [email protected]
