1.1 Million Plants: 14 Years of Volunteers That Healed Onondaga Lake

{“@context”: “https://schema.org”, “@type”: “NewsArticle”, “headline”: “1.1 Million Plants: 14 Years of Volunteers That Healed Onondaga Lake”, “description”: “Onondaga Lake, once labeled America’s most polluted, is now the cleanest it has been in over 100 years. Volunteers and contractors have planted 1.1 million native plants, trees, and shrubs since 2012. Mercury in the water dropped 95 percent. Bald eagles are nesting on the shoreline for the first time since approximately 1800. What worked, what is still broken, and the long arc back to the Onondaga Nation.”, “image”: [“https://upload.wikimedia.org/wikipedia/commons/thumb/6/6d/Bald_eagle_FWS.jpg/1280px-Bald_eagle_FWS.jpg”, “https://upload.wikimedia.org/wikipedia/commons/thumb/f/f8/Wegmans_Landing%2C_Onondaga_Lake_Park%2C_July_2023.jpg/1280px-Wegmans_Landing%2C_Onondaga_Lake_Park%2C_July_2023.jpg”, “https://upload.wikimedia.org/wikipedia/commons/thumb/7/71/Industries_of_War_-_Chemicals_-_BUILDING_OF_SOLVAY_PROCESS_CO.%2C_SYRACUSE%2C_New_York_-_NARA_-_31486726.jpg/1280px-Industries_of_War_-_Chemicals_-_BUILDING_OF_SOLVAY_PROCESS_CO.%2C_SYRACUSE%2C_New_York_-_NARA_-_31486726.jpg”], “datePublished”: “2026-04-27T00:00:00-04:00”, “dateModified”: “2026-04-27T00:00:00-04:00”, “author”: {“@type”: “Organization”, “name”: “CNY Signal”}, “publisher”: {“@type”: “Organization”, “name”: “CNY Signal”, “url”: “https://cnysignal.com”}, “articleSection”: “Conservation”, “keywords”: “Onondaga Lake, Honeywell, Conservation Corps, bald eagle, Syracuse, Superfund, Onondaga Nation, mercury, water quality, restoration”}
{“@context”: “https://schema.org”, “@type”: “FAQPage”, “mainEntity”: [{“@type”: “Question”, “name”: “How many trees and plants have been put on Onondaga Lake’s shoreline since the cleanup began?”, “acceptedAnswer”: {“@type”: “Answer”, “text”: “About 1.1 million native plants, trees, and shrubs have been put into the shoreline and tributaries since 2012, according to figures published by the Onondaga Lake Cleanup Partnership and confirmed by the New York State Department of Environmental Conservation and Audubon New York.”}}, {“@type”: “Question”, “name”: “Is it safe to swim in Onondaga Lake in 2026?”, “acceptedAnswer”: {“@type”: “Answer”, “text”: “Public swimming has not returned to Onondaga Lake. The county has discussed pilot beach plans, but no swimming season has been scheduled. Onondaga County beaches at Oneida Shores and other inland sites open each Memorial Day weekend.”}}, {“@type”: “Question”, “name”: “Is fish from Onondaga Lake safe to eat?”, “acceptedAnswer”: {“@type”: “Answer”, “text”: “Children and women of childbearing age are advised to eat no fish from Onondaga Lake. No one of any age should eat walleye, carp, or smallmouth bass over 15 inches caught in the lake. Mercury levels in walleye and smallmouth bass fillets remain about four times higher than the level the state considers safe for human consumption.”}}, {“@type”: “Question”, “name”: “How many bald eagles winter on Onondaga Lake?”, “acceptedAnswer”: {“@type”: “Answer”, “text”: “Onondaga Lake hosts the largest urban roost of wintering bald eagles in New York State. More than 100 eagles have been counted on a single peak day, drawn by the lake’s south end where the warm Metro plant outflow keeps the water from freezing through winter.”}}, {“@type”: “Question”, “name”: “What was the total cost of the Onondaga Lake cleanup?”, “acceptedAnswer”: {“@type”: “Answer”, “text”: “The estimated total cost of the cleanup plan finalized in the 2006 consent decree was $451 million, including roughly $414 million for construction and about $3 million per year in long-term monitoring and maintenance.”}}]}
{“@context”: “https://schema.org”, “@type”: “LocalBusiness”, “@id”: “https://onondagacountyparks.com/parks/onondaga-lake-park/”, “name”: “Onondaga Lake Park”, “description”: “Onondaga County park along the eastern shore of Onondaga Lake, with multi-use trail, restored shoreline areas, and seasonal events.”, “address”: {“@type”: “PostalAddress”, “streetAddress”: “106 Lake Drive”, “addressLocality”: “Liverpool”, “addressRegion”: “NY”, “postalCode”: “13088”, “addressCountry”: “US”}, “geo”: {“@type”: “GeoCoordinates”, “latitude”: 43.124, “longitude”: -76.228}, “url”: “https://onondagacountyparks.com/parks/onondaga-lake-park/”}

Staff Reporter

The lake that earned the title of America’s most polluted is now the cleanest it has been in more than 100 years. The headline number on this turnaround is 1.1 million. That is the count of native plants, trees, and shrubs that volunteers and contractors have put into the ground around Onondaga Lake since dredging began in 2012.

The volunteer story is bigger than the planting story.

Onondaga Lake sits on the northwest edge of Syracuse, a 4.6 mile slice of water that drains a 285 square mile watershed and once received roughly 25 pounds of mercury per day. From 1946 to 1970, Allied Chemical and its predecessor, the Solvay Process Company, dumped about 165,000 pounds of mercury into the lake bottom along with soda ash byproducts and decades of industrial waste. Swimming was banned in 1940. Fishing was banned in 1970. By 1994, the federal government listed Onondaga Lake as a Superfund site.

What followed is one of the most expensive and most volunteered cleanup efforts in New York State history.

The Before

Before it was a Superfund site, Onondaga Lake was a sacred place to the Onondaga Nation, the central council fire of the Haudenosaunee Confederacy. By the late 1800s it was an industrial sink. The Solvay Process Company, incorporated in 1881, perfected the soda ash process on the lake’s western shore and turned the surrounding waste beds white with calcium chloride sludge. After Allied Chemical absorbed Solvay Process in 1920, the chlor-alkali plant operated through 1986 and used metallic mercury in its electrolytic cells. The mercury bled out of the plant and into the lake’s tributaries.

By the late 1960s, Onondaga Lake’s fish carried mercury at levels the state could not legally permit for sale.

A 1928 fish survey turned up just ten species. The lake’s water was so warm and so loaded with phosphorus and ammonia that algal mats turned the surface to pea soup. Combined sewer overflows from the Metropolitan Syracuse Wastewater Treatment Plant contributed about 20 percent of the lake’s annual inflow and most of its nutrient pollution.

Atlantic States Legal Foundation, a small Syracuse nonprofit founded by Samuel Sage in 1982, filed suit in the 1980s to force Onondaga County to upgrade Metro’s treatment process. That case sat under the surface of the bigger story for decades. Without it, the volunteer plantings would have been throwing seedlings into a chemistry experiment.

The Plan

The cleanup itself ran on three legal tracks. New York State and Honeywell International, the legal successor to Allied Chemical, signed a Consent Decree in October 2006 that locked in a Record of Decision for the lake-bottom subsite. The total estimated cost of the plan was $451 million, including roughly $414 million for construction and about $3 million per year in long-term monitoring. The Onondaga Lake Partnership, the U.S. Environmental Protection Agency, the U.S. Fish and Wildlife Service, and the New York State Department of Environmental Conservation supplied the oversight.

The dredging started in July 2012 and ran through November 2014. Crews removed approximately 2.2 million cubic yards of contaminated sediment from the lake bottom and three shoreline areas, then capped 580 acres of lake bed with a sand and isolation layer mix. By 2016 the cap was complete. By the end of 2017 the DEC announced that Honeywell had finished its share of the remediation work, including dredging, capping, and habitat enhancement.

The numbers in those press releases did not capture the most interesting part of what was happening on the shoreline.

The Volunteers

In the summer of 2012, Honeywell, Onondaga Audubon Society, the Montezuma Audubon Center, and the engineering firms Parsons and O’Brien & Gere stood up the Onondaga Lake Conservation Corps. The pitch was simple. Anyone old enough to hold a shovel could come plant native vegetation on the lakeshore on a Saturday morning. By April 2015, more than 500 volunteers had been through the Corps. Audubon’s own April 2015 announcement that the Corps had won the EPA Region 2 Environmental Champion Award counted 4,500 plants, trees, and shrubs in the ground at that point.

That pace did not slow. By the time the lake-side restoration phase wrapped, the count of plants, trees, and shrubs being put into the lake’s shoreline and tributaries was about 1.1 million, according to figures published by the Onondaga Lake cleanup partnership and confirmed in DEC and Audubon documentation. About 90 acres of wetlands were restored or enhanced.

Schools were a quiet engine. Students from Solvay Middle School and West Genesee Middle School joined Honeywell Summer Science Week field days at the Milton J. Rubenstein Museum of Science and Technology, measuring water velocity in Onondaga Creek and presenting their findings on Discovery Day. Syracuse City school students and kids from the Dunbar Center on the South Side were rotated through the same sessions. Honeywell logged more than 1,200 public meetings, presentations, and tours during the cleanup years, an outreach line item the company had to deliver under the consent decree but that, by the count of bird surveys and shoreline plantings, ended up doing real biological work.

Geddes Brook and Ninemile Creek, two tributaries that drained directly into the lake, became their own restoration projects. Crews replanted floodplains with native willow and silver maple. Wetland cells were graded into the old waste beds. The Geddes Brook wetlands turned into one of the most-watched restoration sites in Central New York, partly because the bird counts began to read like a regional rare-bird report.

The Corps’ own bird counts kept climbing. A single July 2014 birding survey at the Geddes Brook wetlands logged 41 species. By 2017, more than 185 species had been counted at the re-established Geddes Brook and adjacent wetlands. Across the southwest lakeshore, biologists were tracking 110 wildlife species, including more than 75 species of birds.

The Numbers

The water quality story is the part that locks the volunteer story to a result. Mercury concentrations in the lake water dropped about 95 percent after the cleanup. Methylmercury concentrations at the deeper sampling stations, between 10 and 19 meters, fell by about 97 percent versus 2006 levels. Mercury in small prey fish dropped about 75 percent compared with 2010. Phosphorus discharges from the Metro plant fell about 86 percent between 1993 and 2006, the period when Atlantic States Legal Foundation’s lawsuit was driving infrastructure upgrades.

The wildlife caught up. The 1928 survey that found ten fish species was followed by a 1990s survey that captured 54. Today the DEC documents more than 65 species in the lake. More than 250 species of fish, birds, and other wildlife have returned to restored habitat near the lake, according to the cleanup partnership.

The bird that everyone notices is the bald eagle. New York State was down to a single nesting pair of bald eagles statewide in the 1970s. By 2022, biologists at Onondaga Audubon and the DEC confirmed a nesting pair had built on the Onondaga Lake shoreline, the first nest documented along the lake since approximately 1800. The wintering roost on the south end of the lake now draws more than 100 bald eagles in a single day during peak winter weeks. The warm outflow from Metro, the same plant that once made the water unswimmable, keeps the lake’s south end open in winter and concentrates the fish that draw the birds.

On June 10, 2025, the DEC formally accepted the transfer of the Onondaga Lake Visitor Center from Honeywell, an administrative milestone that put the lake’s public-facing education space under state oversight. The center now operates seasonally from April through October under the DEC Bureau of Environmental Education.

What Is Still Broken

The cleanup is not finished, and saying so is not a sour note. The fish carry the largest unfinished business. The state Department of Health still bars children and women of childbearing age from eating any fish from Onondaga Lake. No one of any age should eat walleye, carp, or smallmouth bass over 15 inches caught in the lake. Mercury concentrations in walleye and smallmouth bass fillets have barely budged since 2016, and they remain about four times higher than the level the state considers safe for human consumption.

Charles T. Driscoll, a Syracuse University environmental engineering professor who has studied the lake for decades, has called Onondaga Lake the most successful mercury remediation project in the world while remaining careful about whether the lake will ever support a fully consumable fishery. The next federal EPA five-year review is scheduled for 2030. The state DEC is still reviewing 2023 and 2024 fish tissue test results.

Public swimming has not returned to the lake. Onondaga County beaches at Oneida Shores and other inland sites have opened on Memorial Day weekend each year, but Onondaga Lake itself remains closed to swimming under county order. A county survey on possible reopening drew more than 30,000 responses, and the county has discussed pilot beach plans, but no swimming season has been scheduled.

The equity question runs through everything. The Onondaga Nation has held since the start that the cleanup capped the contamination rather than removing it, and that the lake bottom remains a record of the harm. The Nation’s position on the consent decree has not changed.

The Long Arc

On September 27, 2024, representatives of the Onondaga Nation signed legal documents with Honeywell International for the return of approximately 1,000 acres of land at the headwaters of Onondaga Creek in the Tully Valley. The transfer was facilitated by the U.S. Department of the Interior and the State of New York under provisions of the federal Superfund program and is one of 18 remediation projects mandated as part of the natural resource damage settlement. It was the first acreage returned to the Nation’s stewardship since New York State and the U.S. government repeatedly broke the terms of an 18th-century treaty that had originally set aside 2.5 million acres for the Onondaga.

The headwaters land is an ecological choice as much as a political one. The springs that feed Onondaga Creek end up in Onondaga Lake. Cleaning the source pays back downstream. The Nation has said the returned land will be managed for clean trout and traditional uses.

The 1.1 million figure is the headline because the number is round and verifiable. The story underneath it is more useful. A federal Superfund process, a private chemical company’s legal successor, a small New York legal foundation, a county wastewater plant, two Audubon chapters, four engineering firms, several school districts, hundreds of weekend volunteers, and an Indigenous nation that never left held one shoreline accountable for 14 years. The lake came back. The fish are not all the way back. The next decade will tell whether the volunteers stay.

Sources: New York State Department of Environmental Conservation; U.S. Environmental Protection Agency Superfund Site Profile, Onondaga Lake; U.S. Fish and Wildlife Service; Onondaga Lake Cleanup Partnership; Audubon New York; Onondaga Audubon Society; Atlantic States Legal Foundation; Onondaga Nation; Upstate Freshwater Institute; New York State Department of Health Fish Advisories; Library of Congress Historic American Engineering Record.