Carson River Mercury Site

⚠ Superfund · Cleanup underway

EPA divided the site into two operable units (OUs) to better manage cleanup actions. Operable Unit 1 consists of the old mill sites and tailings. Operable Unit 2 includes the Carson River and adjacent floodplain from the New Empire area to the Carson Sink.

Location

CityDayton
CountyLyon County
StateNevada
Coordinates39.23195, -119.58920

Contaminants of concern

Contaminated media

Cleanup timeline

  1. Initial Assessment Completed — 09/01/1986
  2. Proposed to the National Priorities List — 10/26/1989
  3. Finalized on the National Priorities List — 08/30/1990
  4. Remedial Investigation Started — 09/28/1990
  5. Remedy Selected — 03/30/1995
  6. Remedial Action Started — 09/30/1996
  7. Construction Completed — Not Yet Achieved
  8. Deleted from National Priorities List — Not Yet Achieved
  9. Most Recent Five-Year Review — 09/20/2023
  10. Achieved Sitewide Ready for Anticipated Reuse — Not Yet Achieved

EPA references

Other Superfund sites in Lyon County

EPA-regulated facilities nearby

Understanding this Superfund site

Carson River Mercury Site is a federal Superfund site in Nevada. 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.

Contaminants of concern include arsenic, lead, mercury. Contamination has been detected in 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.