Ritari Post & Pole is a ten-acre former wood-preserving facility near Sebeka in Wadena County, Minnesota. It operated from 1955 to 1991, using creosote and pentachlorophenol (PCP) as wood preservatives. The site was added to the EPA's National Priorities List (NPL) in July 1987, which flags it for formal investigation and cleanup under the federal Superfund program.
The two contaminants of concern are pentachlorophenol and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity equivalents, a measure of dioxin-related risk. Both were found in soil and groundwater. EPA determined that these chemicals pose an unacceptable risk to human health and the environment.
Cleanup work has involved several steps. A remedy was selected in 1994 and updated more than once since then. Contaminated soils containing PCP and dioxin were consolidated on-site into a capped disposal unit, and some additional soil was removed off-site. In 1997, 38 deteriorating drums of PCP solution were removed from the property. Groundwater is tracked through 22 monitoring wells. PCP concentrations above safe drinking water limits have been detected potentially moving off-site to the east and northeast, though most of the contaminated groundwater plume stays on the Ritari property. Institutional controls, including zoning restrictions, prohibit residential use of the site. Physical construction was completed in September 2001, and the Minnesota Pollution Control Agency (MPCA) has overseen ongoing operation and maintenance since September 2002.
Despite construction being complete, two important performance measures remain at an insufficient data status. Assessments have not yet determined whether human exposure pathways are controlled or whether contaminated groundwater movement has stabilized. EPA is planning a new Remedial Investigation and Feasibility Study (RI/FS) for the soil operable unit. That study started in September 2023 and is estimated to finish between late 2027 and early 2028. The most recent five-year review was completed in September 2023, and the next is expected between September and November 2028. The site has not been deleted from the NPL.
Community members can review site documents at the Minnesota Pollution Control Agency office at 520 Lafayette Road North in St. Paul, Minnesota. There are 8 key documents, 8 web content documents, and 16 administrative records on file. For direct questions, contact the EPA's Remedial Project Manager.
