EPA Superfund site

EAST HELENA SITE

Human exposure is NOT currently under control

  • MT
  • EPA ID MTD006230346
  • EPA exposure status as of November 10, 2026

Data limitations: Proximity to a Superfund site boundary does not mean your property is contaminated. EPA site boundaries show the area designated for cleanup, not the full extent of contamination. Groundwater plumes can extend beyond site boundaries. This tool shows publicly available EPA federal data. It is not affiliated with or endorsed by EPA, and is not a substitute for a professional environmental assessment.

About this site's exposure pathways

As of August 2026, the East Helena Superfund site is considered Current Human Exposure Not Under Control (HENC). The primary concern is exposure to lead-contaminated soil in residential yards for Operable Unit 2. Soil sampling in 2023 confirmed at least one exposure situation where children were playing in soil in their yard with an effective soil lead concentration, adjusted for property-specific relative bioavailability, above 1,000 ppm. It is reasonably anticipated that similar exposures also exist at the Site. This exposure pathway is considered unacceptable based on EPA risk-based criteria.

In January 2024, the residential lead cleanup level was modified to 400 ppm through an Explanation of Significant Difference. EPA has entered into an Interagency Agreement with the US Army Corps of Engineers to perform Remedial Action work to remediate residential yards with whole-yard averages greater than 400 ppm soil-lead. The EPA began residential yard cleanups in July 2026. The EPA currently anticipates that human exposure will be under control by December 2036. If you are impacted by risks inherent at this site, contact the Remedial Project Managers, Bridget Williams, at [email protected] or 406-594-8792 (call⁄text) or Jess Smith at [email protected] or 406-438-0825 (call/text).

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