Onalaska Wood Pyrolysis Plant

Site Contact:
Brooks Stanfield
On Scene Coordinator


Site Location:
1674 State HWY 508
Chehalis, WA 98532

The Site includes an 8-acre former sawmill facility that was converted into an industrial facility for the
pyrolysis of wood waste in 2015. The pyrolysis process generated a wood biochar product that was
intended to be sold primarily as a soil amendment for agricultural applications. Two principal byproducts are
also generated through this method of producing biochar: wood tar and wood vinegar.

The original operator – Onalaska Wood Energy, LLC (OWE) – that began pyrolysis activities at the Site,
operated from 2015 to 2018 under a lease agreement. During this period OWE reported to the Washington
Department of Ecology Hazardous Waste and Toxics Reduction Program (Ecology) that concentrations of
toxics in the wood tar and wood vinegar fell below state and federal hazardous waste thresholds and that
there was a market for the product. During this period Ecology received complaints that OWE was dumping waste onto the bare ground, stormwater ponds and into their sewer lines.  OWE was unsuccessful in providing verifiable analytical data to support the claims regarding a nonhazardous waste designation and never successfully identified a market for the waste. In March 2020 the company ceased operations and dissolved the corporation leaving an estimated 100,000 gallons of accumulated wood tar and wood vinegar waste at the Site.

Samples of wood tar and wood vinegar taken by EPA during a 2021 Removal Site Evaluation (RSE) detected elevated concentrations of several hazardous substances in each material. Due to elevated benzene concentrations the wood tar is designated as a D018 characteristic Resource Conservation and Recovery Act (RCRA) Hazardous Waste for toxicity. Two contaminants: 2methylphenol (o-cresol) and 4methylphenol (p-cresol) were detected at high enough concentrations that the waste is designated as a D023 and D024 characteristic RCRA Hazardous Waste for toxicity. The pH of wood vinegar consistently fell between 2.5 and 3.

The abandoned hazardous waste poses a threat of release because of the poor condition of containers, absence of secondary containment, recent history of uncontrolled fires and structural failures, evidence of past releases, and a lack of persons or agencies able to manage the waste appropriately. EPA initiated a Time-Critical Removal Action on June 14, 2021.