2014 Inchelium Wood Treatment Plant Cleanup

Inchelium, WA | Contamination from 1950s–2006 | Clean Up 2014–2016

Site History

The IWTP site began as an equipment maintenance facility in the mid-1950s under Lincoln Lumber Co., later operated by Boise Cascade. In the mid-1980s, after the Tribes acquired the property, Colville Tribal Enterprise Corporation (CTEC) converted it into a pressurized wood treatment plant. From 1985 until 2006, CCA (chromated copper arsenate) was used to pressure-treat wood, creating soil, concrete, and groundwater contamination. In 2006, CTEC ceased operations due to ongoing environmental liabilities and financial losses.

Regulatory Findings

A 2006 EPA inspection exposed major environmental violations:

  • Unpermitted storage of CCA waste and used oils

  • Lack of staff training and safety equipment

  • Use of unlined drip pads and unregistered waste generation

The resulting Consent Agreement and Final Order (CAFO) required:

  • EPA-approved closure and hazardous waste plans

  • Sealing and cleaning tanks, sumps, and drip pads

  • Proper disposal of waste and financial assurances

  • Cleanup actions where CCA had contaminated soil, sump areas, and two under-concrete drip zones

Groundwater tests confirmed elevated levels of CCA contaminants and petroleum products, although monitoring since 2006 shows levels are stable or declining—posing no imminent threat to the drinking water aquifer or Stranger Creek.

Cleanup & Remediation Efforts

After slow progress through 2009–2012, active cleanup began in summer 2014, led by the Environmental Trust Department:

  • Hired a certified hazardous-waste contractor

  • Removed and containerized FO35 hazardous waste from storage tanks and sumps

  • Excavated CCA-contaminated soil and concrete, shipping it off-site for disposal

  • Addressed used-oil containment: backfilled pits and installed new groundwater monitoring wells

  • Started annual groundwater and site monitoring, including a five-year review

  • Brought on an ETD Remediation Specialist for on-site quality control

The goal is to cleanup soil and groundwater to commercial/industrial standards.

Project Funding & Administration

  • Cleanup financed through a $3 million loan from the Qwam Qwmpt Restoration Fund (2.5% interest, 10-year repayment from timber sales)

  • Oversight and funding handled by ETD, prioritizing major contamination sites across the Reservation

Next Steps & Site Use

Future use is still under consideration. The site will meet industrial/commercial safety levels. Continued groundwater monitoring will guide decisions on deeper aquifer risks and plume stability.