
COMMISSION AGENDA – Action Item No. 8h Page 2 of 5
Meeting Date: September 9, 2025
Template revised June 27, 2019 (Diversity in Contracting).
The EWG reached an agreement with EPA on an Order to develop the remedial design for the
cleanup. Under a new cost sharing MOA, the three EWG parties will share responsibility to
implement the required work. The Port will procure an environmental consulting firm to perform
the work, with costs reimbursed by the City and County on a preliminary (subject to reallocation)
basis of 1/3 each. The remedial design work is estimated to cost a total of approximately $30
million. Funding for this work was included in the 2025-2029 Environmental Remediation Liability
(ERL) Program. The request for procurement of a consultant will be completed under a separate
commission request.
BACKGROUND
The Harbor Island Superfund Site is one of the first Superfund sites in the country, listed on the
National Priorities List in 1983. Harbor Island is a human-built, industrial island in Elliott Bay. Built
in the early 1900s, the 420-acre island supports businesses that conduct commercial and
industrial activities, including a former lead battery recycler, ocean and rail transport operations
and petroleum fuel farm storage and operation. Prior operations at the site resulted in
contaminated groundwater, sediment and soil with lead and other contaminants. The EPA
divided the Harbor Island site into six smaller areas, known as “Operable Units” (OUs) to better
address site cleanup. Cleanups have been completed at five of the OUs, and the remaining OU
for cleanup is the East Waterway. The East Waterway cleanup area stretches one mile and covers
157 acres. It is located downstream and north of the Lower Duwamish Waterway Superfund Site,
along the east side of Harbor Island.
The East Waterway is proposed for cleanup due to unacceptable risks to human health and to
the environment. Sediments at the bottom of the waterway contain contaminants that include
polychlorinated biphenyls (PCBs), arsenic, dioxins/furans and carcinogenic polycyclic aromatic
hydrocarbons (cPAHs) that pose risk to human health. There are 29 contaminants, including PCBs
and mercury, which pose risks for benthic invertebrates that are the base of the food chain. PCBs
also pose risk to fish within the waterway. The EPA released its Interim Record of Decision (ROD)
for cleanup of the East Waterway in 2024. The next step to implement the Interim ROD is
Remedial Design.
The EPA oversees the East Waterway cleanup. The EWG, comprising the Port of Seattle, the City
of Seattle, and King County, completed the investigation and feasibility study phase of the
cleanup of the East Waterway operable unit of the Harbor Island Superfund Site. The Port led the
investigation work under a legal agreement with the EPA, supported by the City of Seattle and
King County through a MOA that has been in place since 2006.
The EWG has reached agreement with EPA on an Order to develop the remedial design for the
cleanup. Under a new cost sharing MOA, the three EWG parties will share responsibility to
implement the required work. The Port will procure an environmental consulting firm to perform
the work, with costs reimbursed by the City and County on a preliminary (subject to potential
reallocation) basis of 1/3 each. The Port will hold the contract with the consultant and all