The Washington County Landfill sits on 25 acres in Lake Elmo, Minnesota. It accepted roughly 1.9 million cubic yards of residential, commercial, industrial, and demolition waste from 1969 to 1975. Because the landfill was unlined, waste disposal contaminated soil and groundwater over time. EPA added the site to the National Priorities List in 1984 and later deleted it in 1996 after cleanup goals were met.
The contamination includes 20 chemicals found in groundwater. These include chlorinated solvents such as trichloroethene, tetrachloroethene, and various dichloroethane compounds, along with benzene, acetone, and chloroform. Perfluorochemicals have also been identified. EPA determined all of these pose an unacceptable risk to human health or the environment based on how people could be exposed and how much of each chemical is present.
Cleanup work began in 1984 with a groundwater treatment system using air stripping and extraction wells. In 1993, 72 homes were connected to the public water supply to cut off exposure to contaminated drinking water. The Minnesota Pollution Control Agency (MPCA) took over site management under its Closed Landfill Program in 1995. From 2010 to 2012, MPCA excavated all remaining landfill waste and moved it into a new triple-lined landfill built on site, complete with leachate and gas control systems. In 2015, MPCA added a solar energy system to power those collection systems.
Human exposure is currently under control. Groundwater migration is stabilized, with no unacceptable discharge to surface water. Physical construction of the cleanup is complete across the entire site. All cleanup goals for current and anticipated future land uses have been met, and required land-use controls are in place. EPA's most recent five-year review, completed in 2014, confirmed the site continues to protect human health and the environment. MPCA and the Minnesota Department of Health continue to coordinate on drinking water protection in the surrounding area.
Community members with questions can contact EPA's Community Involvement Coordinator or Remedial Project Manager. Questions can also be directed to the MPCA. Site records are also available for public review at the MPCA office at 520 Lafayette Road North, St. Paul, Minnesota 55155.
