Delta Marine Industries

​Updated January 2025​

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Comments | Comment Response

Cleanup moves forward with Remedial Investigation and Feasibility Study

Ecology held a 60-day public comment period (November 18, 12:00 a.m., 2024 - January 16, 11:59 p.m., 2025) on an Agreed Order and Public Participation Plan. The Agreed Order is an agreement between Ecology, 1608 S 96th St. LLC, and Desimone Trusts requires them to study contamination at Delta Marine Industries, compare cleanup options, and write a draft cleanup plan. The Public Participation Plan describes how Ecology will inform the community about cleanup and ways to become involved.

Ecology has reviewed and considered the public comment received and will finalize both documents. Based on Ecology's evaluation of the comments, no updates were made to the Agreed Order or Public Participation Plan.

The Delta Marine Industries cleanup site is continuing the cleanup process. Ecology will make the future Remedial Investigation and Feasibility Study available for public review and comment.

The Delta Marine Industries site is adjacent to the Lower Duwamish Waterway Superfund Site, which includes a 5-mile stretch of the Duwamish River. The U.S. Environmental Protection Agency (EPA) added the LDW Superfund Site to the Superfund National Priorities List in 2001. Ecology is working to stop or reduce sources of contamination to the LDW Superfund Site, an effort known as “source control,” so that the EPA can proceed with the cleanup of the river sediment.

Location
The Delta Marine Industries cleanup site is located in the vicinity of 1608 S 96th Street and 1801 S 93rd Street in Seattle, Washington. The site includes the Delta Marine property (containing one parcel), which is owned by 1608 S 96th St. LLC, and the Duwamish Yacht Club property (containing three separate parcels) which is owned by the Desimone Trusts. The properties are situated within a mixed-use industrial and commercial zone near the Lower Duwamish Waterway (LDW).

History
This site has been utilized for a variety of purposes over the years. The western portion of the Delta Marine property was primarily used for agricultural purposes until the mid-20th century. By 1969 it transitioned into a yacht-building and repair facility for Delta Marine Industries. The eastern portion of the Delta Marine property was previously occupied by auto wrecking facilities before its redevelopment for marine industrial use. Current structures on the Delta Marine property include storage buildings and shop facilities used for yacht manufacturing.

The Duwamish Yacht Club property was used for agricultural purposes in the early part of the 20^th century, before being converted to commercial and industrial use in the 1960’s.  The Duwamish Yacht Club property has also been used for boat storage and marine industrial activities. The Duwamish Yacht Club is located along the LDW, which has been developed for marina use and includes a clubhouse, office, storage sheds, and several floating docks along the LDW.

A history of industrial and commercial activities near the waterway, along with the use of fill materials which may have been sourced from dredged LDW sediments, have contributed to environmental concerns on both properties.

Contamination
Investigations in 2019 and 2021 found the following contaminants of concern on at the site in various locations:

Soil contaminants:
arsenic, cadmium, lead, thallium, and polycyclic aromatic hydrocarbons (PAHs)

Groundwater contaminants:
petroleum hydrocarbons, antimony, arsenic, lead, and PAHs

Soil vapor contaminants:
petroleum hydrocarbons and volatile organic compounds (VOCs)

The Model Toxics Control Act (MTCA) is Washington’s environmental cleanup law. It provides requirements for contaminated site cleanup and sets standards that protect human health and the environment. Ecology enacts the MTCA and oversees cleanups. The MTCA site cleanup process is completed in steps (see graphic below) over a variable timeline.

Current Delta Marine Industries cleanup site Public Participation Plan

This plan includes information for the public regarding opportunities to get involved in the Site cleanup process. The outreach activities and mechanisms presented reflect Ecology’s current plans for keeping the public informed and for receiving information and comments from the public.