Stimson Lumber Company Located in Bonner, MT this mill processed lumber since the late 1800's. Logs were floated down the Blackfoot River for milling. Processed lumber was then shipped to Butte to support the booming copper mining industry. The mill used a cooling pond that was built into the main channel of the Blackfoot River. In 2006, when the encroaching pond was being removed, pcbs were discovered in the soils in the pond.As this encroachment was removed, more PCB contamination was discovered throughout the site.Cleanup is ongoing and is being overseen by Montana DEQ through a process called Administrative Order on Consent in which responsible parties negotiate clean-up efforts with the Deptartment of Environmental Quality voluntarily. The responsible party in this cleanup is Stimson Lumber Company.

Smurfit-Stone Container Since 1957 Smurfit-Stone Container mill manufactured rolls of liner-board (the material used to cover currogated cardboard). This site was developed on irrigated floodplain. It covers approximately 3,200 acres and is located approximately 11 miles downstream from Missoula on the Clark Fork River. During the height of production, this mill discharged 15 million gallons of wastewater into unlined cells that directly discharge contaminated water into soil and groundwater. At certain times, wastewater was discharged from large pipes directly into the channel. Contaminants in the wastewater and landfills include dioxins, furans and pcbs. This material has been found in fish downstream of the mill and has prompted Montana Fish, Wildlife and Parks to issue a fish consumption advisory.This site is currently up for consideration as a federal superfund site with cleanup overseen by the Montana Deptartment of Environmental Quality.

White Pine & Sash Company The White Pine and Sash company operated on the North side of Missoula between 1920 and 1996 and served as a finish mill that processed logs into trim board, window and door components and other precision woodwork.In order to preserve the wood, it was dipped in a solution of diesel and pentachlorophenol in "dip tanks". Spills and drips and drying lumber impacted soil throughout the property. On the southern end of the site, a injection well (a deep hole designed to rapidly infiltrate into the ground) infiltrated thousands of gallons of this penta mixture. This site has a record of decision (ROD) issued and is being overseen by the Montana Department of Environmental Quality.

Milltown Dam The Milltown dam and reservoir were located in Milltown, Montana, about 4 miles upstream of downtown Missoula. The United States Environmental Protection Agency (EPA) listed the area on the federal Superfund site list in 1983 based on high levels of arsenic detected in area drinking water wells. The dam's powerhouse was removed in March 2008, and spillway removal was completed in March 2009. Contaminated sediment removal and shipment by rail was complete in September 2009. Additional sediment removal for restoration of the site was done and will be completed in 2010. River channel construction and restoration began in 2009 and will continue through 2011. The Clark Fork River will be diverted into its new channel through the remedial project area sometime in late 2010 or early 2011. Design of a new State Park at the former reservoir site will be completed in 2010 and 2011, with construction beginning in 2011.