Aluminum Recycling Trentwood

The Aluminum Recycling Trentwood site is across the Spokane River from the Spokane Valley Mall. Union Pacific Railroad (UPRR) is responsible for site cleanup.

Between 1979 and 1984, the site was used to process and store aluminum. “Primary” and “secondary” aluminum processing was used. The processing created white and black dross as byproducts. When processing ended, two stockpiles of dross were left at the site.

Around 1986, UPRR removed one stockpile and put it in a landfill. In 2017, UPRR removed about 360 cubic yards of the other stockpile to test using it as a raw material in cement production. About 57,000 cubic yards of the second stockpile is left and covers nearly 4 acres.

The remaining stockpile covers an area that includes two neighboring properties. The neighboring properties are owned by Pentzer Venture Holdings II Inc. (Pentzer) and the Washington State Department of Transportation. Pentzer is also legally responsible for cleanup, but UPRR is taking the lead.

White dross contains high aluminum content, and black dross contains high levels of chloride, fluoride, and nitrate.

In 2009, Ecology signed an Agreed Order with UPRR to document the extent and locations of dross contamination (remedial investigation) and evaluate cleanup options (feasibility study) for the site.   

In 2012, Ecology held a public comment period for UPRR's Remedial Investigation and Feasibility Study. We published our responses to comments.

In 2017, UPRR proposed to excavate approximately 360 cubic yards of the mixed waste stockpile to test its use in a recycling process. Ecology held a public comment period for the State Environmental Policy Act checklist we used to determine whether the test would have negative effects on people or the environment and our Determination of Non-Significance. We didn't receive any comments. The results of this test were published in the revised Feasibility Study.

To facilitate a property sale that will allow land to be developed by the community, dross that eroded onto neighboring properties was excavated in spring 2020 and placed back on the large pile. 

From June 9 through July 23, 2021, the draft Cleanup Action Plan, enforcement order, scope of work and schedule, and revised Feasibility Study were available for public comment. In the Cleanup Action Plan, Ecology proposed that UPRR dispose stockpiled aluminum-processing byproducts and contaminated soil at a permitted landfill and cap remaining contaminated soil. The enforcement order is a legal document requiring UPRR to complete the cleanup. Ecology and UPRR could not reach an agreement during the agreed order negotiations, so we issued an enforcement order. The order includes a scope of work and schedule for completing the cleanup. We responded to three sets of comments following the comment period, and modified the Cleanup Action Plan and enforcement order as a result of comments.