EPA Superfund site
ONONDAGA LAKE
Human exposure is NOT currently under control
Data limitations: Proximity to a Superfund site boundary does not mean your property is contaminated. EPA site boundaries show the area designated for cleanup, not the full extent of contamination. Groundwater plumes can extend beyond site boundaries. This tool shows publicly available EPA federal data. It is not affiliated with or endorsed by EPA, and is not a substitute for a professional environmental assessment.
About this site's exposure pathways
As of May 2026, the Onondaga Lake Superfund site is considered “Current Human Exposure Not Under Control” (HENC). Residents and recreational anglers are known or reasonably anticipated to be exposed by eating fish caught from Onondaga Lake and its tributaries. Although dredging and capping of the lake bottom are complete (more than 2 million cubic yards of contaminated sediment removed and about 500 acres of cap placed), fish tissue still shows elevated mercury and polychlorinated biphenyls (PCBs). New York State Department of Health (NYSDOH) fish consumption advisories are in place and advisory signs are posted, but subsistence fishing continues.
Currently, the planned activities to address this pathway include:
- Completing the remedial investigation/feasibility study (RI/FS) for regional deep groundwater and implementing any needed source‑control actions to reduce contaminant loading to the lake and tributaries.
- Advancing several remaining remedial designs and remedial actions at contributing subsites to control ongoing inputs.
- Continuing long‑term fish tissue, sediment, and water monitoring to evaluate cap performance and trends in mercury and PCBs, and adapting management if needed.
- Maintaining and updating institutional controls, including NYSDOH fish consumption advisories and posted signage, and conducting targeted outreach to subsistence fishers.
If you may be affected, you can reduce your exposure by not eating fish caught from Onondaga Lake and its tributaries, practicing catch‑and‑release, and following posted signs and NYSDOH advisories. For assistance, contact the Community Involvement Coordinator Larisa Romanowski via the site webpage or at (518) 407-0400 or [email protected].
EPA currently anticipates that human exposure will be under control by September 2048 because remaining source‑control remedies will be implemented, long‑term monitoring is expected to demonstrate declining fish tissue concentrations of mercury and PCBs to risk‑based cleanup goals, and institutional controls will remain in place and effective until fish consumption risks are acceptable, as reflected in the Superfund Enterprise Management System (SEMS) and consistent with NPL deletion milestones.