South Andover Site

Overview

From 1954 to 1981, about 50 acres in Andover, Minnesota were used for waste disposal and salvage operations. That activity left soil and groundwater contaminated with hazardous chemicals. EPA added the site to the National Priorities List (NPL) in 1983, making it a federally designated Superfund site. The site goes by several other names, including Heidelberger Cecil Property, Musket Ranch, and Pumpkin City Investments.

EPA has identified 21 contaminants of concern. Groundwater contains chlorinated compounds including vinyl chloride, tetrachloroethene, and several dichloroethane and trichloroethane variants, along with organic solvents like acetone and toluene, and metals such as cadmium, chromium, lead, and nickel. Soil contamination includes lead, antimony, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs).

Cleanup is organized into three operable units covering groundwater, source control, and a third unit with no decision document on file. Responsible parties completed soil removal, bioremediation, and thermal treatment by 1994. EPA partially deleted the site from the NPL in 1998 after that work was finished. Groundwater cleanup focused on monitored natural attenuation. A vinyl chloride plume in the southwest portion of the site has been shrinking since 1998, but 2020 sampling found concentrations at 18 micrograms per liter, well above the cleanup standard of 2 micrograms per liter. Monitoring continues until the standard is met. A new remedial investigation for the groundwater operable unit began in May 2024, with completion estimated between December 2027 and February 2028.

New concerns have emerged in nearby neighborhoods. In 2022, the Minnesota Pollution Control Agency found 1,4-dioxane and PFAS (per- and polyfluoroalkyl substances) in private wells north of the site in the Red Oaks neighborhood. In 2023, 1,4-dioxane turned up in private wells to the southwest in Eastbrook Terrace. The source of these contaminants has not been determined, though the South Andover site and a nearby closed landfill are considered potential sources. EPA has asked the responsible parties to investigate whether 1,4-dioxane and PFAS are present at the South Andover site and could be contributing to the nearby well contamination. EPA currently considers human exposure at the main site to be under control, though the new well detections are part of ongoing investigation. The most recent five-year review was completed in September 2021, with the next one estimated for July through September 2026.

The site has been redeveloped as a light industrial and commercial zone. The Andover Station commercial development and townhomes now occupy the area, supporting over 500 jobs annually. Community members with questions or observations about site conditions can contact EPA's Community Involvement Coordinator or Remedial Project Manager.