Milltown Reservoir Sediments

⚠ Superfund · Cleanup underway

​​The site is managed in operable units (OUs).

Location

CityMilltown
CountyMissoula County
StateMontana
Coordinates46.86452, -113.88336

Contaminants of concern

Contaminated media

Cleanup timeline

  1. Initial Assessment Completed — 05/01/1982
  2. Proposed to the National Priorities List — 12/30/1982
  3. Finalized on the National Priorities List — 09/08/1983
  4. Remedial Investigation Started — 06/27/1983
  5. Remedy Selected — 04/14/1984
  6. Final Remedy Selected — 12/15/2004
  7. Remedial Action Started — 05/04/1984
  8. Construction Completed — Not Yet Achieved
  9. Deleted from National Priorities List — Not Yet Achieved
  10. Most Recent Five-Year Review — 08/05/2021

EPA references

Other Superfund sites in Missoula County

EPA-regulated facilities nearby

Understanding this Superfund site

Milltown Reservoir Sediments is a federal Superfund site in Montana. The Superfund program, created by Congress in 1980, addresses sites where hazardous substances have been released or threaten release into the environment. EPA scores potential sites using the Hazard Ranking System; those that score high enough are placed on the National Priorities List.

Current status: Cleanup underway. Active cleanup is underway, meaning EPA has approved a remediation plan and work is in progress. Cleanup timelines vary widely — some sites take decades depending on contamination depth, groundwater involvement, and funding availability.

EPA has identified 6 contaminants of concern at this site, including arsenic, cadmium, copper. Contamination has been detected in soil, surface water, solid waste, groundwater.

If you live near this site and have health concerns, your state health department can provide site-specific guidance. EPA maintains a community involvement program for most NPL sites, and site documents — including the Record of Decision, five-year reviews, and public health assessments — are typically available through EPA's Superfund site profile.