Lake Calumet Cluster covers 87 acres in southeastern Chicago. The site was originally wetlands before steel mills and other industries began dumping slag, debris, and chemical waste there in the early 1900s. Unauthorized industrial, chemical, and municipal waste disposal continued from the 1940s through the 1980s. EPA placed the site on the National Priorities List (NPL) in March 2010.
Contamination affects soil, sediment, groundwater, and surface water. More than 50 chemicals have been identified as contaminants of concern. These include volatile organic compounds (VOCs) such as benzene, trichloroethene, and chloroform, heavy metals including lead, arsenic, cadmium, and chromium, polychlorinated biphenyls (PCBs), pesticides such as heptachlor, and polycyclic aromatic hydrocarbons (PAHs) like benzo(a)pyrene. EPA determined these substances pose an unacceptable risk to human health or the environment.
The cleanup is divided into four operable units (OUs) covering sitewide concerns, the landfill area, groundwater, and a fourth unit called SEMS that has a Record of Decision (ROD) from September 2006. That 2006 decision selected a low-permeability clay cap, a gas collection system, and institutional controls for the landfill area. Cap construction began in December 2006 but remains incomplete. EPA is coordinating cap completion with the groundwater remedy to avoid having to redo work. Potentially responsible parties signed an agreement in 2013 to investigate groundwater. Three phases of groundwater investigation were completed between 2015 and 2017. EPA expects to finalize the groundwater investigation report by early January 2027, followed by a feasibility study and proposed cleanup plan in fall 2027, with a final remedy decision tentatively set for spring 2028. The most recent Five-Year Review was completed in September 2024 and confirmed the current approach is working as intended. Land use restrictions and groundwater use restrictions are in place to prevent exposure while cleanup continues.
Community members can get involved through several channels. EPA plans to release a proposed cleanup plan for public comment in fall 2027. Available public documents include the 2024 Five-Year Review report, a June 2024 fact sheet in English and Spanish, a 2022 Community Involvement Plan, and a 2021 EPA presentation given at the Southeast Environmental Task Force Meeting.
