Eastern Michaud Flats Contamination

⚠ Superfund · Cleanup underway

To manage the site, EPA divided the site into three separate cleanup areas called operable units: the former FMC Plant OU, the Simplot Don Plant OU and the Off-Plant OU. Also, the FMC OU encompasses closed hazardous waste ponds regulated by EPA’s Resource Conservation and Recovery Act Program.

Location

CityPocatello
CountyNot Defined County
StateIdaho
Coordinates42.90111, -112.52250

Contaminants of concern

Contaminated media

Cleanup timeline

  1. Initial Assessment Completed — 09/06/1985
  2. Proposed to the National Priorities List — 05/05/1989
  3. Finalized on the National Priorities List — 08/30/1990
  4. Remedial Investigation Started — 05/30/1991
  5. Remedy Selected — 06/08/1998
  6. Final Remedy Selected — 09/27/2012
  7. Remedial Action Started — 08/01/1997
  8. Construction Completed — Not Yet Achieved
  9. Deleted from National Priorities List — Not Yet Achieved
  10. Most Recent Five-Year Review — 09/23/2025

EPA references

Other Superfund sites in Not Defined County

EPA-regulated facilities nearby

Understanding this Superfund site

Eastern Michaud Flats Contamination is a federal Superfund site in Idaho. 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 10 contaminants of concern at this site, including alpha gross, antimony, arsenic. Contamination has been detected in groundwater, soil.

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.