Aluminum Recycling Trentwood

Between October 2022 and July 2023, Union Pacific Railroad (UPRR) disposed waste and contaminated soil at a landfill. Remaining contaminated soil was consolidated on UPRR’s property and capped with a protective cover, so animals and people can’t contact it. Two other properties that were part of the site, owned by Pentzer Venture Holdings II Inc. (Pentzer) and the Washington State Department of Transportation, are now clean. 

We removed the site from the Contaminated Sites List in December 2024, after holding a public comment period and receiving no comments.

Between 1979 and 1984, the site was used to process and store aluminum. “Primary” and “secondary” aluminum processing was used. The processing created dross as byproducts. When processing ended, two waste stockpiles 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 was left and covered nearly 4 acres.

The remaining stockpile covered an area that included two neighboring properties owned by Pentzer and the Washington State Department of Transportation. Pentzer was also legally responsible for cleanup, but UPRR took the lead.

The waste stockpiles contained metals (arsenic, barium, chromium, copper, and mercury) at levels requiring cleanup and were a risk to neighboring properties and the Spokane River.

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.

In spring 2020, waste that eroded onto neighboring properties was excavated and placed back on the large pile, although not all waste was removed.

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 on UPRR's property. 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 included 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.

The capped area of contaminated soil on UPRR's property is fenced and signs warn people of the remaining contamination. UPRR will inspect the cap's condition every year. The environmental covenant filed with Spokane County on UPRR's property ensures current and future property owners know about the capped contamination.