Thirty-two years after Onondaga Lake landed on the federal Superfund list, the EPA is conducting its third five-year review of the lake-bottom cleanup, and Central New York is still waiting for a final answer on whether the fix will hold.
The review, launched in 2025, examines whether the dredging and capping work Honeywell International completed between 2012 and 2017 continues to protect public health. It arrives at an awkward moment: fish tissue sampling data from catches after 2018 still has not been fully analyzed due to laboratory errors and bureaucratic delays, leaving a gap in the evidence regulators need.
A Lake That Nearly Died
The damage stretches back to the 1880s, when the Solvay Process Company began dumping industrial waste along the western shore. Over the next century, more than 165,000 pounds of mercury flowed into the lake. By 1940, swimming was banned. By 1970, fishing followed. At its worst, Onondaga Lake carried the label of the most polluted lake in America.
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The turnaround required a staggering investment. Between Honeywell and Onondaga County, roughly $1.5 billion has been spent on research and remediation. Workers dredged 2.2 million cubic yards of contaminated sediment from the lake bottom, then covered 475 acres with more than 3 million cubic yards of clean capping material, sand, activated carbon, siderite, and stone, to seal remaining contaminants in place.
What the Numbers Show
The results, on paper, are striking. Methylmercury in deep-water portions of the lake has dropped 98 percent since 2009. Sixty-five fish species now swim in water that once supported fewer than a dozen. Water quality in the northern two-thirds of the lake meets public health standards for swimming, a sentence nobody could have written 30 years ago.
Onondaga Lake By The Numbers
Can You Actually Swim in It?
Technically, parts of the lake meet the standard. Onondaga County has proposed a $5.1 million swimming beach on the northern end. But a county survey found only two in 10 residents would feel safe taking a dip, a trust deficit that decades of pollution earned. Fishing reopened back in 1986, though consumption advisories remain. The state tells anglers to avoid eating largemouth and smallmouth bass over 15 inches, walleye, carp, channel catfish, and white perch entirely. Women under 50 and children under 15 should eat no fish from the lake at all.
The Lakefront Is Changing Around It
While the environmental work continues below the surface, the shoreline is changing fast. COR Development has poured $75 million into the Inner Harbor at the lake’s south end, where the Iron Pier apartments are fully leased with a waiting list. An $85 million aquarium is under construction on the harbor’s north side. New I-81 ramps and the Spencer Street bridge now connect Syracuse’s Northside directly to the waterfront.
The Creekwalk, the 4.8-mile paved trail linking downtown Syracuse to the lake, remains one of the region’s most popular routes for runners, cyclists, and kayakers. Crews are now building a bridge to carry the Loop the Lake trail over CSX railroad tracks near Destiny USA, the most complex section yet in the effort to create a continuous path around the entire shoreline.
Meanwhile, Onondaga County’s Save the Rain program has installed more than 230 green infrastructure projects that capture 190 million gallons of stormwater each year, pushing the combined sewer capture rate to 98.1 percent, well above the 95 percent target set in 2009.
The Debate That Won’t Settle
Not everyone accepts the progress at face value. The Onondaga Nation, for whom the lake holds deep spiritual significance, argues that capping is containment, not cleanup. Their experts estimate a full remediation would cost $2.16 billion, nearly five times Honeywell’s approved plan. They point out that roughly 10 million cubic yards of contaminated sediment remain under those caps, and question how long the barriers will last.
The next chapter may hinge on the EPA’s five-year review findings and the Ley Creek cleanup, where $30 million in federal and settlement funds will tackle contaminated floodplain soil starting in spring 2027. On April 18, the Onondaga Lake Conservation Corps will host an Earth Day shoreline cleanup, a reminder that for all the billions spent, keeping this lake clean is still a hands-on job.
