Colville Post and Pole, Inc. (CPPI), located approximately four miles outside of Colville, Washington, was a wood-treating facility that used pentachorophenol/diesel (PCP) treating solutions to manufacture predominantly PCP-treated fence posts and rails. Wood-treating operations occurred on the 23-acre site for approximately 60 years under several different owners and companies. Wood-treating operations at this location consisted of heated solution dip tanks and an adjacent drip pad with treated wood product being stored over soil in various locations in the yard. The Site is located within 200 feet of the Colville River and its associated riparian ecosystem and habitats for threatened species. The river is a tributary to Lake Roosevelt (the Upper Columbia River), currently under investigation with the EPA Region 10 Remedial Program for impacts from contaminated sites within the drainage area.
Over the past 15 years, Washington State Department of Ecology (Ecology) has provided CPPI and owners Resource Conservation and Recovery Act (RCRA) oversight during facility upgrades and several release incidents of PCP/diesel from piping, drip pads, and ruptured ASTs. In August 2000, The Confederated Tribes of the Colville Reservation (CCT) petitioned the US EPA Region 10 Site Assessment Unit to conduct a Preliminary Assessment of the Site. The Site Assessment Unit referred the site to EPA RCRA because it was an operating facility. Because of history of releases at the Site and known SPCC compliance issues, EPA RCRA coordinated with EPA CERCLA in October 2002, and conducted a Removal Site Evaluation (RSE) of CPPI and found PCP, dioxin, and diesel contamination in surface and subsurface soils, and PCP/diesel contamination in groundwater and surface water. A SPCC inspection of the PCP/diesel tanks and a review of the facility’s SPCC Plan found CPPI to be out of compliance with the SPCC regulations.
Over the next two years EPA RCRA and CERCLA Removal programs conducted several inspections of the facility with findings indicating that there were ongoing violations of RCRA, the Clean Water Act SPCC requirements, and a need for the company to undertake additional assessment and cleanup activities under CERCLA to address contamination at the Site. CPPI determined that they were unable to secure the resources to upgrade the facility and conduct the necessary cleanup to meet regulatory requirements and decided to cease operations at the facility for an indefinite period of time.
Consistent with its mission to protect human health and the environment and to reduce the threat of further harm to the environment from this Site, EPA Region 10 commenced with a Time-Critical Removal Action to be conducted in two phases. Phase I of the removal consisted of actions needed to secure the facility, restrict access, and stabilize the hazardous waste onsite for transportation and disposal off-site as the owner ceased operations in January 2005.
In June 2005, the EPA Removal program conducted a Phase II Removal Site Evaluation and installed a monitoring well network to characterize groundwater contamination. After a year of quarterly groundwater sampling and monitoring it was determined that the shallow groundwater was contaminated with PCP and diesel and it was migrating off site in a westerly direction, potentially impacting residential drinking water wells downgradient.
A Phase II Removal Action was initiated in September 2006 to excavate contaminated soil in the Process Area and transport/dispose off site in a regulated landfill. Once the contaminated soil source is removed it is anticipated that contamination in the shallow groundwater will attentuate with time. Additional monitoring wells will be installed, four more quarters of sampling will be conducted and the data used to conduct modeling in an attempt to determine where the contamination is going and how long it might take to clean up. A soil cover will also be installed with hydroseeding to control wind and water erosion of low levels of contamination remaining in several areas of the site.
