A former pesticide manufacturing plant that operated near Hiawatha Avenue and 28th Street from 1938 to 1963 spread arsenic trioxide powder into the Phillips, Longfellow, and Powderhorn neighborhoods of south Minneapolis. Wind carried the powder off site, contaminating soil across roughly 1,480 acres. High arsenic levels turned up in 1994 during a street reconstruction project, and EPA added the site to its National Priorities List in September 2007.
Arsenic in soil is the only contaminant of concern. The main health risk comes from swallowing contaminated soil, either through eating unwashed root vegetables grown in it or from children putting dirty hands in their mouths. Smaller risks come from breathing arsenic dust or touching contaminated soil. Groundwater is not currently a health threat because the area relies on public water supply.
Cleanup happened in two broad phases. Between 2004 and fall 2008, EPA excavated soil at 196 properties where arsenic levels were dangerously high. A second phase, funded in part by the American Recovery and Reinvestment Act, tackled about 500 more properties where arsenic posed long-term but not immediate risk. That work finished in September 2011, one year ahead of schedule. In total, EPA cleaned up more than 600 properties and removed over 50,000 tons of contaminated soil. The community section notes that EPA has completed investigation and cleanup of more than 3,600 residential properties overall. Additional remedial action work continued from January 2016 through January 2017 and again from November 2017 through March 2022, and a final remedial action phase is estimated to begin between June and August 2028.
Properties that received cleanup are available for unlimited use with unrestricted exposure. Human exposure is now under control, and no unacceptable exposure pathways remain. Three partial deletions from the National Priorities List have been completed, in September 2019, September 2021, and August 2024. One property remains on the list and will be removed once cleanup is complete or institutional controls are in place. EPA completed its most recent five-year review in March 2024. Property owners are required by city ordinance to disclose EPA testing results to potential buyers. For properties where owners denied access, the city withholds rental permits to encourage cleanup when selling or applying for those permits.
Community members with questions can contact the EPA's Community Involvement Coordinator or Remedial Project Manager. Public records are available at three Minneapolis locations: the Central Library on Nicollet Mall, the East Lake Branch of the Public Library, and the Corcoran Neighborhood Organization office on Cedar Avenue South.
