Perham Arsenic Site

Overview

From the 1930s until 1947, a facility at this site mixed arsenic with sawdust and molasses to make a grasshopper pesticide. Around 200 to 2,500 pounds of that pesticide were buried in a shallow pit in 1947, contaminating nearby soil and groundwater. The site was added to the National Priorities List (NPL), the federal roster of the most serious hazardous waste sites, with final listing in September 1984.

Arsenic is the only contaminant of concern. It affects groundwater and, historically, soil around the buried pit. The risks are serious: EPA determined arsenic posed an unacceptable risk to human health based on the amount present and the potential effects of exposure. In the 1970s, eleven employees at an adjacent property were poisoned after drinking arsenic-contaminated well water, which led to that property being connected to the public water supply.

Cleanup has moved through several phases. Workers removed arsenic waste and contaminated soil from the pit, then installed a landfill cap over it. A groundwater extraction and treatment system was built between 1997 and 1998, and one residence was connected to the public water supply in 1994. Major construction wrapped up in September 1998. Institutional controls are in place to restrict uses like residential development that could expose people to remaining contamination.

Today the site is in operation and maintenance. EPA's most recent five-year review, completed in July 2021, confirmed that cleanup actions continue to protect human health and the environment in the short term. Human exposure to contamination is under control, and groundwater migration is stabilized. EPA will keep monitoring to ensure contamination stays in its original area. The site earned "Sitewide Ready for Anticipated Use" status in 2010, meaning cleanup goals have been met for current and expected land uses. As of December 2024, three businesses on the property employed six people and generated roughly $748,380 in annual sales. The site remains on the NPL and has not been deleted. The next five-year review is expected between July and September 2026.

Community members with questions can contact the EPA's Community Involvement Coordinator or Remedial Project Manager. Administrative records covering site investigations, cleanup decisions, and regulatory actions are also available for review.