The Armour Road site covers 1.8 acres in North Kansas City, Missouri. A herbicide mixing facility operated there from the 1920s until 1986, using arsenic as a primary ingredient. That arsenic contaminated both soil and groundwater in the Missouri River alluvial aquifer. The site was discovered in 1989, assessed in 1991, and added to the National Priorities List in May 1999.
Several rounds of cleanup have already removed contaminated soil. Between 2004 and 2006, the building was demolished and arsenic-contaminated soil was excavated and sent to permitted landfills. In January 2017, crews removed additional contaminated soil from beneath a nearby road and a neighboring property that were off-limits during earlier work. Some contamination still sits beneath Armour Road itself and will require future action if that pavement is ever removed.
In September 2022, EPA issued an Interim Record of Decision for the remaining soil and groundwater contamination. The selected remedy uses in-situ immobilization with permeable reactive zones, a chemical treatment applied underground to trap arsenic and stop it from spreading through the aquifer. The plan also includes annual groundwater monitoring, institutional controls that restrict groundwater use, and limits on excavating contaminated soil. A restrictive covenant filed in 2004 at the Clay County Recorder's office already prohibits groundwater use in the arsenic plume area. EPA is negotiating a consent decree with responsible parties to carry out the remedy. Remedial design is estimated to run from mid-2026 through mid-2027, with remedial action set to begin between December 2027 and February 2028.
Residents get their drinking water from the public water supply, so drinking water exposure is not a pathway of concern. EPA assessments indicate that human exposure is under control and contaminated groundwater is stabilized with no unacceptable discharge to surface water. Even so, physical construction of the cleanup is not yet complete, and the site does not yet meet the criteria for readiness for anticipated use. The former industrial property has already been redeveloped into retail and residential use, with a restaurant and medical building now operating on site. As of December 2024, three on-site businesses employed 45 people and generated about $6,490,000 in annual sales.
Community members with questions can contact EPA's Community Involvement Coordinator. Site records are available for public review at the North Kansas City Public Library at 2251 Howell Street.
