Region 8
Serving Colorado, Montana, North Dakota, South Dakota, Utah, Wyoming and 27 Tribal Nations
Milltown Reservoir Sediments/Clark Fork River Superfund Site
NEW: EPA is conducting a 5-Year Review at the Silver Bow Creek/Butte Area site. We will periodically post relevant information.
5-Year Review announcement
In 1981, Missoula County health officials discovered arsenic contamination in drinking water wells in Milltown, Montana. The wells were located near the Milltown Dam and Reservoir. To protect public health, EPA provided an alternative water supply to affected area residents and in 1982, proposed listing the site on the National Priorities List for cleanup under Superfund. The Site was made final on the NPL in 1983.
EPA divided the Milltown Reservoir Sediments/Clark Fork River Superfund Site into 3 parts called Operable Units (OUs):
- Milltown Drinking Water Supply OU (this OU is now addressed as part of the Reservoir Sediments OU)
- Milltown Reservoir Sediments OU
- Clark Fork River OU