Feasibility of former lumber mill site

Client Name
Avison Lumber Company
Oregon, USA
  • Land quality & remediation


In April 2016, SLR conducted a feasibility study for the Avison Lumber Company, located in Molalla, Oregon. The former mill company produced lumber from the 1950s to 1990’s and was sanctioned by the Oregon Department of Environmental Quality (DEQ) to perform extensive cleanup before redevelopment. Soil at the site had been contaminated with dioxins associated with historic pentachlorophenol anti-fungal applications to lumber prior to shipping. The feasibility study evaluated options to manage contaminated soil.

The site consists of two parcels totalling over 90-acres.


SLR developed a cleanup plan that proposed a variety of remedial technologies depending on the setting (e.g., wetlands, uplands), projected land use (e.g., future industrial location, open space), and degree of contamination.

A relatively small volume of the most contaminated soil will be excavated and disposed off-site. Moderately impacted soil will be excavated, placed on the land parcel preparing for redevelopment, and covered with an engineered cap.


The engineered cap will serve as a platform for future commercial/industrial operations. An innovative technology will be used to treat contaminated soil in wetlands and other natural areas. Activated carbon will be applied to soil to sequester dioxins in-situ, reducing the ability of dioxins to bioaccumulate in the food chain, and minimizing disturbance natural wetland systems. Wetland restoration will be performed in some of the excavation areas.