Health & Environment

What Are the Risks at the Site?

Site investigations have indicated that the former integrated pulp and paper mill site is contaminated with arsenic, manganese, and dioxins/furans in limited areas proximal to the former industrial area. EPA has finalized formal human health and ecological risk assessments for all three Operable Units (OUs): OU1, which is primarily agricultural land, OU2, the former core industrial area, and OU3, the former settling ponds areas along the Clark Fork River floodplain. EPA updated the risk assessments in 2026 to incorporate sampling data from 2024’s additional sampling events.  

EPA completed the human health risk assessment for the largely agricultural portion of the site (OU1) in 2017 and concluded that OU1 does not pose a human health concern. 

• 2017 Human Health Risk Assessment for OU1 (pdf) (99 pp, 8.3 MB, About PDF)

EPA also completed the Ecological Risk Assessment for OU1 and found that diverse effects to plants and small mammals from selenium is possible but unlikely and recommended no action. 

• 2017 Final Ecological-Risk Assessment for OU1 (pdf) (113 pp, 7 MB)

EPA finalized the Operable Units 2 and 3 Human Health Risk Assessment and the Baseline Ecological Risk Assessments in 2021 and 2022. Those reports are available below: 

• Final Human Health Risk Assessment for Smurfit Stone Frenchtown Mill Operable Unit 2, December 2021 (pdf) (364 pp, 4 MB)
• Final Human Health Risk Assessment for Smurfit Stone Frenchtown Mill Operable Unit 3, April 2022 (pdf) (1343 pp, 35 MB)
• Final Baseline Ecological Risk Assessment for Operable Units 2 and 3 of Smurfit Stone Frenchtown Mill Site, October 2021 (pdf) (1506 pp, 22 MB)