The top court posted the decision on its website without further detail.
The pipeline has put Prime Minister Justin Trudeau’s Liberal government, which bought it in 2018 to ensure the expansion overcame legal and regulatory obstacles, in a political quandary. He has promised to reduce greenhouse gas emissions and improve federal relations with indigenous peoples, but is under pressure to help the oil industry, which is key to the national economy.
Expansion of the 67-year-old pipeline, which runs from Alberta to the British Columbia coast, is well underway. It would nearly triple capacity to 890,000 barrels per day.
The Federal Court of Appeal dismissed challenges in February to the Canadian government’s second approval of the project, which has faced years of delays. They were based on concerns from British Columbia indigenous groups that Ottawa had not meaningfully consulted them.
Three of those groups – Coldwater Indian Band, Squamish Nation and Tsleil-Waututh Nation – sought to appeal the decision. The indigenous communities have raised environmental concerns, such as the risks of oil spills.
Western Canadian pipelines have been chronically congested for years, but this year, space has opened as plunging oil prices led producers to curtail production.