A historical timeline of important events affecting pollution in Onondaga Lake.

1654: Explorers discover salt springs on the shores of Onondaga Lake.
 
1783: Revolutionary War ends. European settlements develop in Central NY.
 
1793: Commercial salt production begins on the lakeshore.
 
1822: Lake level is lowered for drainage of Syracuse swamps.
 
1880: Onondaga Lake is a popular resort area. The west shore of the lake has many hotels, parks and bathing beaches. Swimming, boating and fishing are common activities during the summer season.
 
1884: The Solvay Process Company (later to become Allied-Signal Corp.) begins production of soda ash.
 
1901: Ice harvesting is prohibited.
 
1918: The Solvay Process Company begins production of organic chemicals.
 
1925: City of Syracuse begins the removal of settleable solids from sewage (primary treatment).
 
1940: Swimming is banned.
 
1946: Allied begins chlorine production by the mercury cell process. Mercury wastes are discharged directly into the lake.
 
1960: Construction of the Onondaga County Metropolitan Wastewater Treatment Plant (Metro) is completed.
 
1970: Fishing is banned. Due to the discovery of mercury in the lake's fishery, the US Attorney General sues Allied-Signal to stop mercury dumping. The amount of mercury discharged to the lake is calculated to be 22 lb/day.
 
1971: Onondaga County bans high phosphorus in laundry detergents.
 
1973: New York State bans phosphorus in laundry detergents.
 
1977: Allied closes chlorinated benzene plant and Willis Avenue chlor-alkali plant.
 
1979: Metro is upgraded to secondary and tertiary treatment.
 
1986: Allied closes soda ash manufacturing operations.
 
1987: Onondaga County implements best management practices for sewer interception. Combined sewer overflow events are reduced by 90%.
 
1988: Atlantic States Legal Foundation, the Attorney General and DEC file complaint against Onondaga County Department of Drainage and Sanitation alleging violation of its state discharge permit. LCP-Hanlin shuts down Bridge Street chlor-alkali plant due to illegal dumping of mercury.
 
1989: Attorney General and DEC file a complaint against Allied-Signal Corp. for pollution violations and resource damage.
 
1990: The Onondaga Lake Management Conference is convened in Syracuse by U.S. Senator Daniel Patrick Moynihan.
 
1991: Onondaga Lake Management Conference begins lake research and remediation projects. Pump stations at Liverpool and Ley Creek are completed to eliminate raw sewage overflows to the lake.
 
1992: Corps of Engineers completes the Onondaga Lake Water Quality Technical Report outlining possible lake remediation alternatives. The Onondaga Lake Management Conference funds a major study of mudboil effluents and potential remedial solutions. Mud discharges to Onondaga Lake average 30 tons per day.
 
1994: The Onondaga Lake Management Conference begins aquatic habitat restoration projects in Onondaga Lake.
 
1995: The Onondaga Lake Management Conference completes mudboil remediation projects to reduce flow of sediment to Onondaga Creek. Onondaga Lake added to Federal Superfund National Priority List.
 
1996: Allied-Signal continues Remedial Investigation and Feasibility Study of Onondaga Lake. New York State, Onondaga County and Atlantic States Legal Foundation continue negotiation over remediation of Metro and CSO impacts on the lake.
 
1997: DEC, Atlantic States Legal Foundation and Onondaga County reach agreement on wastewater treatment plant improvements and a schedule to attain compliance with the Clean Water Act, signing an Amended Consent Judgment (ACJ). The DEC and Allied-Signal agree to an expedited schedule which shortens the Remedial Investigation / Feasibility Study process on the Allied-Signal lake bottom consent decree by two years.
 
1998: The Federal Judge signs the Amended Consent Judgment (ACJ) ordering interim wastewater treatment plant improvements agreed upon by the DEC, Atlantic States Legal Foundation and Onondaga County.
 
2000: On August 9, 2000 the Onondaga Lake Partnership (OLP) was established to promote cooperation among Federal, State, and Local Governments, and other involved parties in the management of the watershed and environmental issues of Onondaga Lake.