Site Description
Terminal 117 (T-117), formerly known as the Malarkey Asphalt Plant, is located at 8700 Dallas Avenue South on the west side of the Duwamish River in South Park. The site has been restored as currently a habitat restoration site and community park now known as Duwamish River People’s Park. The site is adjacent to The Boeing Company and South Park Marina.
Site History
The Duwamish Manufacturing Company and Malarkey Asphalt Company operated at the site beginning in 1937. 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 intent to build a maritime cargo terminal.
In 2003, the US Environmental Protection Agency (EPA) designated the site as an “Early Action” area with the Lower Duwamish Waterway (LDW) Superfund Site due to the significant contamination at the site. 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. The Site has been fully remediated and is now a habitat restoration site that includes a public access area and park.
What is the Port’s Role in this Cleanup?
The Port and the City of Seattle jointly performed the site cleanup under EPA’s oversight. Following completion of the cleanup, the Port restored 14 acres of critical fish and wildlife habitat along with 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 will continue to monitor the effectiveness of the cleanup and to ensure that it remains effective in 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.
Construction of Duwamish River People's Park was completed 2022.
Contact Information
Joanna Florer | Senior Manager, Environmental Programs | [email protected]
