Kaiser Aluminum & Chemical Corporation
15000 E Euclid Ave, Spokane, WA 99216

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Kaiser Aluminum & Chemical Corporation’s Trentwood facility (Kaiser Trentwood) produces aluminum sheet, plate, and coil for aerospace and general engineering applications.

The federal government built the facility during World War II, and it first produced aluminum sheet in 1943. After the war ended, the facility was sold to private interests and has processed aluminum since.

Materials used in past aluminum production included polychlorinated biphenyl (PCB) oil, petroleum fuels, solvents, and chromium. Wastes generated as a result of past or present operations are wastewaters, chrome sludge, paint and solvent wastes, and black dross.


Several releases of contamination have occurred at the Kaiser Trentwood site due to historical operations. Kaiser investigated the contamination and conducted cleanup actions to address groundwater and soil contamination coming from these releases. 

Remedial investigation and feasibility study

In 2010, Kaiser investigated nine areas at the site to better understand contaminants in soil and groundwater, where they were located, and how much was present at the site. 

Since completing the investigations, Ecology requested more information about the west discharge ravine area, where wastewater was formerly discharged to the Spokane River. This investigation more clearly defined possible sources of PCB contamination in groundwater.
The feasibility study evaluated information from the investigations and outlined cleanup options for contaminants in soil and groundwater at the site.
    • Please visit the Technical Reports section of the document repository to view the multi-volume remedial investigation and feasibility study.

    Interim cleanup actions and groundwater pilot test leading to final cleanup plan

    Kaiser has completed many interim cleanup actions, including removing petroleum on groundwater and excavating or capping contaminated soil. PCB contamination in groundwater is the primary remaining issue.

    Kaiser pilot tested a pump-and-treat system to remove PCBs from groundwater. The system filters groundwater through crushed walnut shells to capture the contaminants. However, new technologies to remove PCBs from groundwater have been identified since the agreed order was first amended to include testing a walnut-shell filtration system. Research shows these new technologies could be more effective and result in a shorter cleanup timeframe, so additional testing was proposed. The testing will help us select the most appropriate cleanup technology for removing PCBs from groundwater at the site.

    We held a public comment period on the Amendment to Agreed Order No. 2692, State Environmental Policy Act checklist, and our Determination of Non-significance February 24 through April 22, 2020. We responded to comments from 15 people. Based on requests, we extended the comment period 30 days and held a public meeting April 8:

    Watch the online meeting | Download the presentation

    When the draft cleanup action plan is written, it will be available for public review before becoming final.


    Map showing site location as Spokane County, WA SITE INFORMATION


    View Electronic Documents

    Cleanup Site Details Report

    Facility Site ID: # 53481373

    Cleanup Site ID: 7093

    Spokane, Spokane County

    Status: Cleanup Started   Get definitions of Status terminology

    Jeremy Schmidt
    Site Manager
    (509) 329-3484

    Erika Beresovoy
    Public Involvement Coordinator
    (509) 329-3543

    Document Repositories:

    Eastern Regional Office
    N 4601 Monroe St
    Spokane, 99205-1265

    Spokane Valley Public Library
    12004 East Main
    Spokane Valley, 99216