The Upper Clark Fork Basin, which stretches 120 miles from Butte to Missoula, was heavily impacted by mine wastes washed down Silver Bow Creek and the Clark Fork River from Butte and Anaconda, settling throughout the floodplain and backing up against the Milltown Dam near Missoula, just after the confluence of the Clark Fork and Blackfoot Rivers. The Milltown Reservoir / Clark Fork River Superfund Site is divided into three Operable Units: Clark Fork River, Milltown Water Supply, and Milltown Reservoir Sediments. The Milltown OUs can be considered as one unit for practical purposes.
Upstream, the Anaconda Smelter Site sits on the east side of the town of Anaconda, near the headwaters of the Clark Fork River at the south end of the Deer Lodge Valley. Near the Anaconda Site is the BP-ARCO Waste Repository, also known as the Opportunity Ponds, a site formerly used as a tailings pond complex for the Anaconda Smelter, now used to contain wastes excavated elsewhere in the basin as part of ongoing cleanup.
- Detailed site documents can downloaded via the Superfund Library, and refer to specific site pages for many additional details and updates.
- For information on the settlement on the lawsuit between the State of Montana and ARCO, which is funding much of the restoration work around the Clark Fork, visit the Montana Department of Justice Natural Resource Damages Program (NRDP).
- The Clark Fork River Technical Assistance Committee (CFRTAC) also provides information and outreach in regards to the Clark Fork River Superfund sites and Operable Units.
- The Clark Fork Coalition is also an active community group in regards to Superfund and environmental cleanup related to Missoula and the greater Clark Fork River.
- Visit the website of the Arrowhead Foundation, the EPA-funded TAG group for the Anaconda area.
- Visit the website of the Opportunity Citizens Protection Association (OCPA), a grassroots community group concerned about environmental issues related to the BP-ARCO Waste Repository near Anaconda and Opportunity.