The Idaho Pole Co. site covers about 87 acres north of Bozeman, Montana. Wood treating operations ran there from 1945 to 1997, first using creosote and later pentachlorophenol (PCP) mixed with carrier oil. A railway roundhouse also operated on the property before the wood treating era. The site was added to the federal Superfund National Priorities List (NPL) in June 1986, making it eligible for federal cleanup funding and oversight.
Contamination affects soil, groundwater, and sludge on the property. EPA identified 13 contaminants of concern. These include PCP, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and seven polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene and dibenzo(a,h)anthracene. These substances pose risks to human health and the environment. The main exposure concerns are drinking contaminated groundwater and trespassers contacting treated soils or active remedy areas.
Cleanup has moved through several phases. About 24,000 cubic yards of contaminated soil were excavated and treated on site between 1995 and 2002. Treated soil was returned to the ground and covered with at least 12 inches of clean soil. A groundwater recovery system ran from 1997 to 2018, removing roughly 60 pounds of PAHs and 290 pounds of PCP before being shut down as its effectiveness declined. Since 2016, nutrient injections have been used to encourage natural bacteria to break down remaining contamination. In August and September 2022, additional amendments were injected into the source area south of Interstate 90, and a permeable reactive barrier was installed north of I-90 to keep remaining contaminants from spreading further. Groundwater monitoring at residential properties has not detected contaminants since sampling began in the 1990s.
A partial deletion from the NPL for the soils and groundwater area occurred in January 2020. The site reached "sitewide ready for anticipated reuse" status in September 2010. About 41 acres south of I-90 were purchased by Scout DAC, LLC in October 2022 for redevelopment, following a Prospective Purchaser Agreement with EPA and the Montana Department of Environmental Quality (MDEQ). Institutional controls remain in place, restricting groundwater use and limiting digging and construction without EPA and MDEQ approval. A feasibility study for the soils and groundwater operable unit began in July 2022, with a removal action estimated to start between September and November 2026.
EPA completed its sixth five-year review in September 2025 and found the remedy to be short-term protective. Three issues need follow-up: establishing a formal inspection schedule for treated soil areas, studying whether updated floodplain maps require additional action, and conducting a vapor intrusion study for the chemical 1-methylnaphthalene in groundwater. Community members can review the Sixth Five Year Review Report and a January 2024 fact sheet through EPA's Superfund records system, or in person at the Bozeman Public Library at 626 East Main or the EPA Superfund Records Center in Helena at 10 West 15th Street, Suite 3200.
