The first season Onondaga Lake reopens for the summer with a state-owned visitor center instead of a Honeywell-owned one is now. A decade after the dredging machines went silent, the picture for 2026 splits cleanly in two. Water chemistry has rebounded. Capping is holding. Wetlands are working. Mercury concentrations in the fish people eat have not moved. The state fish consumption advisory stays in place, the lakeshore is open for swimming on the public beach side, and a 1,023-acre return of ancestral land to the Onondaga Nation in the Tully Valley has changed the political math around what restoration even means.
The lake is small. Onondaga is 4.6 miles long, one mile wide, with a surface area of 4.6 square miles, a maximum depth of 63 feet, and a mean depth of 35 feet. Compared with Skaneateles to the south or any of the bigger Finger Lakes to the west, it is a pond. Compared with the contamination it inherited, it is a federal Superfund site. Between 1946 and 1970, Allied Chemical and Dye Corporation discharged roughly 165,000 pounds of mercury into the lake from its Solvay Process Company facility on the west shore. The Solvay plant operated from 1881 through 1986. Salt mining and soda ash production left the western shoreline coated in waste beds that are still being managed today.
The cleanup ran on the 2005 federal Record of Decision. Honeywell, which inherited the liability when it acquired the AlliedSignal businesses in 1999, was the responsible party. Dredging took place between 2012 and 2014. Roughly 2.2 million cubic yards of contaminated sediment came out of three shoreline areas and the lake bottom. The capping phase, between 2014 and 2016, placed more than three million cubic yards of sand, activated carbon, siderite iron ore and stone over 580 acres of lakebed. Cleanup activities for the lake itself were officially complete in late 2016. Habitat restoration around the shoreline wrapped in 2017. Honeywell’s responsibility under the consent decree did not end at that point. Long-term monitoring of the cap and the wetlands is a contractual obligation that runs in perpetuity.
This story came from public records we pulled ourselves
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The single most visible change in 2026 is who holds the keys to the Onondaga Lake Visitor Center on the west shore. The building opened in 2012 as a Honeywell facility designed to walk schoolchildren and Saturday visitors through the cleanup story. In June 2025, after a long-running plan reached its negotiated conclusion, Honeywell transferred the property to the New York State Department of Environmental Conservation. DEC’s Bureau of Environmental Education runs the building going forward. The center continues to open seasonally, April through October. The contents of the exhibits will be refreshed under state ownership, but the building itself, the parking lot, the trails out behind it, and the deep-water fishing pier on the lake are now state property.
The fish consumption advisory tells the other half of the story. The New York State Department of Health advisory on Onondaga Lake remains restrictive a decade after the dredgers stopped running. No one should eat walleye, carp, or any smallmouth bass longer than 15 inches caught in the lake. Children and women of childbearing age should eat no fish at all from the lake. The advisory is anchored on mercury concentrations in fish tissue, and the tissue numbers have barely moved. In 2024 reporting from the Watertown Daily Times, mercury levels in the fillets of walleye and smallmouth bass, which sit at the top of the lake’s food chain, had barely budged since 2016. Mercury concentrations had fallen in the water, in the invertebrates at the base of the food web, and in the small fish that eat those invertebrates. Top predators are slow to track those changes because mercury is concentrated up the food chain.
Honeywell’s monitoring data release has been uneven enough to draw public criticism. The company has released only four years of usable fish-tissue data in the decade since dredging ended. A private laboratory contracted for the 2019 and 2020 sampling work mishandled the fish-flesh testing, voiding two years of data. The most recent data publicly available are from fish caught in 2022. DEC has stated that 2023 and 2024 results are in review and should be released by fall 2026. Critics, including the Onondaga Nation and a group of academic limnologists at SUNY ESF and Syracuse University, have argued that the gaps in data make any claim of cleanup success premature. DEC’s response in public statements has been that the cap is performing as designed and that the consent decree obligates ongoing review.
The wetlands restoration figures are more straightforward. Parsons, the international infrastructure firm acting as Honeywell’s environmental contractor on the lake, is responsible for maintaining 100 acres of restored wetlands around the shoreline. Jim Molloy, a senior scientist with Parsons, walked WAER through the work last summer. Along the Western Shoreline, about 10 acres of wetlands have been restored in low-lying areas, including new habitat for turtles and amphibians. At the Southwest Lakeshore and Harbor Brook, 14 acres of wetlands were created, with shallower zones designed to benefit wetland-spawning fish and deeper sections aimed at sport fish. Near the mouth of Nine Mile Creek, more than 18 acres of in-lake and shoreline wetlands were established using roughly 150,000 native plants. A pollinator garden added in 2025 sits alongside that work.
The political layer that did not exist a generation ago is the 2018 Natural Resource Damage Assessment settlement. In that year the US Department of the Interior and New York State settled an NRDA claim with Honeywell and Onondaga County valued at over $26 million. The settlement covers releases of mercury and other hazardous substances into the lake and its tributaries between 1881 and 1986. The Onondaga Nation participated in the NRDA process. The final addendum to the restoration plan landed in March 2024 from the US Fish and Wildlife Service and DEC, with project-by-project updates.
The most consequential outcome of that addendum was the November 2024 transfer of 1,023 acres of ancestral homeland in the Tully Valley to the Onondaga Nation. The Nation accepted fee title to a 758.1-acre South Forest Nature Preserve and a 264.9-acre North Forest Nature Preserve. The combined parcels include the headwaters of Onondaga Creek, more than 45 acres of wetland and floodplains, and roughly 980 acres of forest and successional fields. Attorney General Letitia James, Governor Kathy Hochul, US Fish and Wildlife Service Director Martha Williams and Onondaga Nation Chiefs announced the transfer jointly. A separate project, led by the Central New York Land Trust in partnership with the Nation, is developing educational programs for City of Syracuse and Onondaga Nation students at the 300-acre Pleasant Valley Preserve, on ancestral lands west of the lake.
On the recreation side, summer 2026 is a busy season. Onondaga Lake Park runs the West Shore Trail, a 7-mile paved path from Salina to Geddes, owned and operated by Onondaga County Parks. The deep-water fishing pier is open with catch-and-release rules and adaptive fishing tools available for anglers of all abilities. The Empower Federal Credit Union Amphitheater at Lakeview, which sits at the north end of the lake in the Town of Geddes, has a summer concert schedule that includes a free Moonlight Movie Series on July 2, July 9 and July 16, 2026. Gates open at 5:30 p.m. and the first feature starts at 6:00 p.m. Onondaga County Parks publishes the full calendar at events.onondagacountyparks.com. Swimming is permitted on the public beach side. Boats are subject to a 5-mile-per-hour no-wake zone in some areas of the lake. The single public reminder that has not been removed is the wading sign near the cap zone, which advises against disturbing the sediment cap with anchor drops or dragging gear.
The Onondaga Nation’s position on the cleanup is on the public record at onondaganation.org/land-rights. The Nation has consistently described the cleanup as incomplete. The Nation argues that the cap covers but does not remove the mercury, that the upland Solvay waste beds on the west shore remain a long-term groundwater concern, and that the failure to fully clean Geddes Brook, Ninemile Creek and the tributary network upstream of the lake means contamination will keep cycling. The 2024 land return in the Tully Valley does not replace that critique. It adds an ancestral-stewardship dimension to a federal Superfund site that was previously framed almost entirely as an engineering problem.
The technical question for the next decade is whether the cap holds and whether the food web continues to detoxify on its current path. DEC’s lake monitoring program, which is described at dec.ny.gov/nature/waterbodies/watersheds/management/great-lakes/onondaga-lake, runs annual sampling of water column, sediment, and biota. Honeywell remains the responsible party for the data collection under the consent decree. EPA Region 2 maintains the Superfund site profile at cumulis.epa.gov as site identifier 0203382. The Onondaga Nation, with academic partners, is doing parallel monitoring that does not depend on Honeywell’s data release schedule.
What changes for a Syracuse resident in 2026 is small but tangible. The visitor center on the west shore now flies a New York State flag instead of a Honeywell sign. The fish advisory still applies. The fishing pier is still open and accessible. The Onondaga Nation now owns more than a thousand acres of forest and wetland that drain into the watershed feeding the lake. The cap underneath the water is sixteen feet thick in places and built to last centuries. None of that means the cleanup is over. It means the next phase is monitoring, and the public-facing parts of that monitoring are now split between three or four institutions instead of one.
Reporting by Jen Okafor for CNY Signal. Sources: NYSDEC June 2025 press release on Onondaga Lake Visitor Center transfer; US EPA Superfund Site Profile 0203382; Watertown Daily Times investigation on post-cleanup fish mercury, 2024; ITRC Remediation Management of Complex Sites Onondaga Lake case study; US Fish and Wildlife Service Onondaga Lake Natural Resource Damage Assessment Restoration Plan addendum dated March 2024; New York State Attorney General announcement November 2024 on Tully Valley land transfer to Onondaga Nation; NYSDOH Fish Consumption Advisory; Parsons Onondaga Lake Habitat Restoration documentation; Onondaga Nation public statements on the cleanup at onondaganation.org/land-rights; Onondaga County Parks event calendar at events.onondagacountyparks.com.
