1899----Dominion Iron & Steel Company Ltd. (DISCO) begins construction of steel plant on eastern shore of Wintering Cove in Sydney Harbour.
1901----DISCO mill, largest steel mill in North America, begins production.
1912----DISCO steel mill is producing nearly half the steel made in Canada.
1920----DISCO and Nova Scotia Steel & Coal Company Ltd. form British Empire Steel Corporation (BESCO), which takes over Sydney mill.
1930----The Dominion Steel and Coal Corporation (DOSCO) buys Sydney mill.
1957----Hawker-Siddley Group buys mill. About the same time, Dominion Tar and Chemical Co. (DOMTAR) abandons its chemical plant at northwest corner of Coke Ovens, leaving derelict tanks behind.
1967----Hawker-Siddley announces closure of plant.
1968----Province of Nova Scotia buys plant, forms crown corporation, Sydney Steel Corp. (Sysco), to run it.
1968----Government of Canada buys Coke Ovens, forms Crown corporation, Cape Breton Development Corporation (Devco), to run them.
1971----Coke production reaches record levels. Devco builds Tar Cell to hold 25,000 tonnes of unmarketable byproducts.
1973----Sysco takes over Coke Ovens from Devco.
1976----Proposal to replace Sysco with new mill at Gabarus falls through.
1982----Fisheries scientists find PAHs from Tar Ponds in Sydney Harbour lobsters. South Arm of harbour closed to lobster fishing indefinitely.
1986----Canada and Nova Scotia sign $34.2 million, 70/30 agreement to dredge Tar Ponds. Sediments to be pumped through mile-long pipeline to CFB incinerator & power plant that will generate electricity.
1988----Coke Ovens close.
1990----Steel making at Sysco converts to electric arc furnace, allowing open hearth furnaces to close.
1991----With work on incinerator 90 per cent complete, cost-share agreement expires. Province continues project alone.
1994----Incinerator commissioned and passes air emissions tests but problems with pipeline prevent it from going into operation.
1995----Problems with pipeline continue. Nova Scotia Power offers only 3 cents per kilowatt hour, not the expected 5-6 cents. Having spent $17.8 million after end of cost share, province considers other options.
1996----Province proposes to bury Tar Ponds under slag from steel plant. Some residents condemn plan.
1996----Federal and provincial ministers meet to consider community-based process to find acceptable solutions.
1996----The Joint Action Group (JAG) formed.
1998----Three levels of government and JAG sign MOU.
1999----Ottawa, Nova Scotia, and Cape Breton Regional Municipality (CBRM) sign $62-million cost-sharing agreement to fund scientific studies, surface cleanup, and JAG activities.
2001----Province closes steel plant and creates Sydney Tar Ponds Agency to manage cleanup of Tar Ponds and Coke Ovens.
2002----Engineered containment system transforms old dump into grassy hillside, while slashing flow of leachate into Coke Ovens. Interceptor sewer enables diversion of raw sewage from Tar Ponds. Major demolition projects completed.
2003----JAG provides cleanup recommendation to government. In response, Environment Canada and Sydney Tar Ponds Agency formulate cleanup plan.
2004----Canada and Nova Scotia commit $400 million to cleanup plan. Sydney Tar Ponds Agency will manage cleanup. Public Works and Government Services Canada (PWGSC) takes over from Environment Canada as federal lead department. Province files detailed Project Description.
2005----May: Acting on recommendation of federal Public Works Minister Scott Brison, Environment Minister Stephane Dion orders full panel review of cleanup plan, the most rigorous form of environmental assessment available. Dion sets unusually tight timelines, ordering panel to report by June 30, 2006. Following negotiations, Nova Scotia agrees to participate.
2005----August: Following public consultation, federal and provincial environment ministers release final guidelines for Environmental Impact Statement (EIS). CEAA issues revised timeline.
2005----September: Ministers appoint panel members Leslie Griffiths (chair), William Charles, and Louis Lapierre. Griffiths was chair of Voisey's Bay panel review. Charles was Dean of Dalhousie Law School. Lapierre co-chaired the Citizen's Liaison Committee for the highly successful cleanup of CN Rail's Moncton Shops.
2005----November: Canadian Environmental Assessment Agency hands out $170,000 in funding to help groups prepare for panel hearings.
2005----December: Province submits seven-volume, 3000-page EIS on December 28, plus 27-page summary in plain language. Public has until February 16, 2006, to submit comments on EIS to panel.
2006----April: Joint Panel holds three weeks of public hearings on the Sydney Tar Ponds Agency's Environmental Impact Statement.
2006----June: Construction begins on a barrier across the mouth of Muggah Creek. This is an important step necessary to protect Sydney Harbour from further pollution as the big cleanup proceeds.
2006----July: Review Panel delivers its report with 55 recommendations to federal and provincial governments. Government response to the report is expected by year-end.
2006----August: Battery Point Barrier is completed, ahead of schedule, and under budget.
2006----October: Partnership of Earth Tech and CBCL, two internationally respected engineering consulting firms, win $30 million contract for final design and construction oversight for the Tar Ponds and Coke Ovens cleanup.
2006----November: Two-year, $6-million project to realign the Coke Ovens Brook is substantially complete.
2007----January: The Government of Canada and the Province of Nova Scotia responds favourably to the panel report, giving the Sydney Tar Ponds Agency approval to begin the cleanup.