Ninth Avenue Dump is a former chemical and industrial waste disposal site in Gary, Indiana, listed on EPA's National Priorities List (NPL) on September 8, 1983. Disposal activities from the early to mid-1970s left soil and groundwater heavily contaminated. The site is divided into three cleanup areas: an oil phase unit, a soil and groundwater unit, and sitewide operations. Cleanup has been underway for decades, and the site remains on the NPL.
EPA identified 17 contaminants of concern across soil, groundwater, and free-phase liquid contaminants that do not mix with water (called nonaqueous phase liquid, or NAPL). These include benzene, vinyl chloride, trichloroethene, toluene, xylene, lead, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), heptachlor, cyanide, and metals, among others. Groundwater once held roughly 100 organic and inorganic substances. A layer of oil floated on groundwater in parts of the site. Contamination has largely stayed within the original operating area, though it spread on the eastern and northeastern sides. High dissolved solids and chlorides also migrated from an off-site road salt storage pile to the south. Many substances are no longer detected.
Cleanup actions included extracting and treating oil and groundwater, installing a landfill cap, building an on-site groundwater treatment system, and setting up long-term groundwater monitoring. Oil phase work ran from December 1990 to July 1993. The soil and groundwater unit began remedial action in February 1994 and ran through September 2004, after which it moved into operation and maintenance under EPA oversight. Physical construction is complete across the entire site. A feasibility study for the soil and groundwater unit is estimated to take place between August and October 2028.
EPA completed its sixth five-year review on May 29, 2025, and found the remedy protective of human health and the environment in the short term. Human exposure is currently under control. However, groundwater migration status remains uncertain due to insufficient data on whether contaminated groundwater movement has stabilized. Cleanup goals affecting current and future land uses have not been fully met for the entire site. Zoning restrictions and other institutional controls limit land uses that would be unsafe given current cleanup levels, but those controls are still being finalized. The site has not been deleted from the NPL.
Community members with questions can contact EPA's Community Involvement Coordinator or Remedial Project Manager. For state-level concerns, the Indiana Department of Environmental Management (IDEM) can also be contacted.
