OTTAWA — The federal cabinet's long-awaited decision on the Trans Mountain pipeline expansion is due Tuesday. Here are some other key dates in the history of the original project and Kinder Morgan Canada's controversial efforts to expand its capacity:
October 1953: The Trans Mountain pipeline begins shipping oil with an initial capacity of 150,000 barrels per day. The project initially features four pump stations along its 1,150-kilometre route and a marine dock that connects loading facilities on the east side of Edmonton with ocean tankers in Burnaby, B.C. It is expanded in 1957 and 2008 to eventually pump up to 300,000 barrels of oil per day.
Feb. 21, 2012: Kinder Morgan Canada says it wants to expand the Trans Mountain pipeline after receiving support from oil shippers and will begin public consultations.
Dec. 16, 2013: An application is made to the National Energy Board (NEB) to expand the Trans Mountain pipeline. Construction is proposed to begin in 2017, with the aim of having oil flow through the expansion by December 2019.
November 2014: More than 100 people are arrested after they camp out in a conservation area on Burnaby Mountain, east of Vancouver, to block crews from conducting drilling and survey work related to the pipeline expansion. Most of the charges are later dropped.
August 2015: The NEB postpones public hearings after striking from the record economic evidence prepared by a Kinder Morgan consultant who was to begin working for the regulator.
Jan. 27, 2016: The federal Liberal government says assessments of pipeline projects such as the Trans Mountain expansion will now take into account the greenhouse gas emissions produced in the extraction and processing of the oil they carry. Proponents will also be required to improve consultations with First Nations.
May 17, 2016: Ottawa appoints a three-member panel to conduct an environmental review of the Trans Mountain expansion project.
May 29, 2016: The NEB recommends approval of the pipeline, subject to 157 conditions, concluding that it is in the public interest.
Nov. 29, 2016: Prime Minister Justin Trudeau approves the Trans Mountain expansion, part of a sweeping announcement that also saw approval of Enbridge's Line 3 pipeline replacement, but the end of its Northern Gateway project.
Jan. 11, 2017: B.C. Premier Christy Clark announces her support for the project, saying Kinder Morgan has met five government conditions including a revenue-sharing agreement worth up to $1 billion.
May 25, 2017: Kinder Morgan makes its final investment decision to proceed with the development, now estimated to cost $7.4 billion, subject to the successful public offering of Kinder Morgan Canada.
May 29, 2017: The B.C. NDP and Greens agree to form a coalition to topple the Liberal party, which could only manage a minority in the previous month's provincial election. The parties agree to "immediately employ every tool available" to stop the project. The coalition defeats the B.C. Liberals in a confidence motion a month later, paving the way for John Horgan to become premier.
Aug. 10, 2017: The B.C. NDP government hires former judge Thomas Berger to provide legal advice as it seeks intervener status in the legal challenges against the project filed by municipalities and First Nations.
Dec. 7, 2017: NEB allows Kinder Morgan Canada to bypass Burnaby bylaws.
Jan. 17, 2018: Kinder Morgan Canada warns the Trans Mountain expansion project could be a year behind schedule.
Jan. 30, 2018: B.C. government moves to restrict any increase in diluted bitumen shipments until it conducts more spill response studies, a move that increases the uncertainty for Trans Mountain.
March 23, 2018: Green party Leader Elizabeth May and NDP MP Kennedy Stewart are arrested at a protest against the pipeline expansion; Federal Court of Appeal dismisses a B.C. government bid challenging a NEB ruling that allows Kinder Morgan Canada to bypass local bylaws.
April 8, 2018: Kinder Morgan Canada suspends non-essential spending on the Trans Mountain expansion project and sets a May 31 deadline to reach agreements with stakeholders.
May 29, 2018: Federal government announces deal to buy the pipeline and expansion project from Kinder Morgan Canada for $4.5 billion.
Aug. 30, 2018: The Federal Court of Appeal overturns the Trudeau government's approval of the pipeline expansion. In a unanimous decision by a panel of three judges, the court says the NEB's review of the project was so flawed that the federal government could not rely on it as a basis for its decision to approve the expansion.
Sept. 15, 2018: Natural Resources Minister Amarjeet Sohi orders the NEB to undertake a new environmental assessment of the impact additional oil tankers off the coast of British Columbia will have, with a specific focus on the risks to southern resident killer whales. The NEB has until late February to report back.
Sept. 26, 2018: The NEB assigns a new panel to run the hearings and sets deadlines for comments.
Oct. 3, 2018: Natural Resources Minister Amarjeet Sohi hires former Supreme Court of Canada Justice Frank Iacobucci to oversee a new round of Indigenous consultations. No deadline is set for the completion of the process.
Feb. 22, 2019: The NEB recommends to cabinet that it approve the project again, subject to 16 new conditions, and says although an oil spill could be significant, the project provides considerable benefits and there are measures that can be taken to minimize the effects. The federal cabinet has 90 days — until May 22 — to respond with a decision.
Apr. 18, 2019: Sohi announces cabinet has decided to push the pipeline decision back until June 18 citing a need to take more time to complete Indigenous consultations.
June 18, 2019: Federal Liberal government approves the expansion a second time, requiring that all federal revenue it generates be reinvested in clean energy and green technology, including an estimated $500 million a year in new annual corporate tax revenues and the proceeds from the sale of the entire expanded pipeline back to the private sector.