The St. Augusta Sanitary Landfill/Engen Dump is a 48-acre former landfill in St. Augusta Township, Minnesota. It accepted municipal, commercial, and industrial waste from 1966 to 1982. The EPA added it to the Superfund National Priorities List in July 1987 and deleted it in November 1996.
The landfill contaminated soil and groundwater with heavy metals including arsenic, barium, and lead, along with volatile organic compounds, atrazine, and phthalates. These contaminants posed risks through direct contact with landfill waste and through ingestion of or contact with contaminated soil and groundwater.
Cleanup focused on consolidating three separate fill areas onto the St. Augusta Landfill site, installing a final landfill cap, and putting an active gas extraction system in place. Remedial design ran from January to May 1996, and the remedial action phase ran from May 1996 through September 2000. The Minnesota Pollution Control Agency (MPCA) led cleanup work and continues to oversee operation and maintenance through its Closed Landfill Program. No further action for groundwater was required. The EPA conducted five-year reviews in 2003 and 2008 to track progress.
Human exposure is currently under control, with no unacceptable exposure pathways identified across the site. Groundwater migration is also under control, with contaminated groundwater stabilized and no unacceptable discharge to surface water. Physical construction of the cleanup is complete. However, the site has not yet achieved sitewide ready-for-anticipated-use status, meaning some cleanup goals or required land-use controls are still being finalized. Institutional controls remain in place, with zoning restrictions blocking residential development and other uses incompatible with the cleanup level achieved. The landfill cap and gas extraction system require ongoing maintenance.
Community members with questions can contact the EPA's Community Involvement Coordinator or Remedial Project Manager. For operation and maintenance questions, contact the MPCA. Site records are available for public review at the MPCA office at 520 Lafayette Road North, St. Paul, Minnesota 55155.
