Superfund Site: ONONDAGA LAKE

Superfund Site Profile

To view the 2017 Third Five-Year Review for the Ley Creek PCB Dredging subsite:  click here

To view the First Five-Year Review for the Hiawatha Blvd Former Municipal Gas Plant (MGP) subsite:  click here

To view the First Five-Year Review Report for the Geddes Brook/Ninemile Creek site:  click here


Onondaga Lake is located along the northern side of the City of Syracuse in Onondaga County, New York. The lake itself covers an area of 4.6 square miles. Its shoreline borders the city of Syracuse, as well as the towns of Geddes and Salina and villages of Solvay and Liverpool. The site includes the lake and seven major and other minor tributaries and upland sources of contamination. The lake receives water from a drainage basin of approximately 285 square miles, located almost entirely within Onondaga County. Effluent from the Metropolitan Syracuse Wastewater Treatment Plant discharges into the southeastern end of the lake. The lake flows into the Seneca River, which flows into the Oswego River. The Oswego River ultimately flows into Lake Ontario.  

Onondaga Lake has been the recipient of industrial and municipal sewage discharges for more than 100 years. The availability of salt and limestone along and in the vicinity of Onondaga Lake led Honeywell International, Inc.’s (Honeywell’s) predecessor companies (e.g., Solvay Process Company, Allied Chemical Corp. and AlliedSignal, Inc.) to locate along the west side of the lake. In 1946, Allied Chemical started a mercury cell process that resulted in waste streams containing mercury and heavy metals being discharged by its facilities at Willis Avenue and Bridge Street. Honeywell’s Semet Residue Ponds are another source of contamination to the lake. While Honeywell is the site’s primary potentially responsible party (PRP), other industrial and manufacturing facilities located along the shore or tributaries to the lake are sources of contamination to the lake. Site investigations and cleanup activities are ongoing. The EPA and New York State have determined that the site poses no immediate threat to human health or the environment while studies are underway.