Northside Sanitary Landfill covers about 65 acres near Zionsville in Boone County, Indiana. From the 1950s through the 1980s, the site received over 16 million gallons of hazardous waste. It was added to the National Priorities List in September 1984 and has been in active remediation ever since.
Contaminants are found mainly in groundwater and leachate. They include volatile organic compounds such as trichloroethene, tetrachloroethene, benzene, toluene, vinyl chloride, and 1,1,1-trichloroethane. Heavy metals including arsenic, lead, chromium, nickel, copper, iron, and zinc are also present. Phthalates, ammonia, phenol, naphthalene, and polycyclic aromatic hydrocarbons round out the list. Iron and benzene are the contaminants EPA has flagged as ongoing concerns in groundwater monitoring.
Cleanup construction began in September 1994 and finished in September 1996. The remedy includes a hazardous waste cap with gas venting, a hydraulic isolation wall, leachate and groundwater collection systems with off-site treatment, and fencing. In 2009, EPA added an on-site constructed wetland treatment system. Operation and maintenance activities continue, and institutional controls, including zoning restrictions that block incompatible residential uses, remain in place. EPA has determined that human exposure is under control and groundwater migration is stabilized with no unacceptable discharge to surface water.
EPA completed five-year reviews in April 2019 and April 2024. Both confirmed that the remedy continues to protect human health and the environment in the short term. Continued protectiveness depends on keeping up operation and maintenance activities and maintaining institutional controls. The site has not yet been deleted from the National Priorities List.
Community members can review site documents at the Hussey-Mayfield Memorial Library at 250 N. Fifth Street in Zionsville. The site has 16 key documents and 54 administrative records available through EPA's Superfund records system. For questions, residents can contact the EPA's Community Involvement Coordinator or Remedial Project Manager.
