Canada's TC Energy, a leading North American energy company based in Calgary, Canada and operator of the infamous Keystone Oil Pipeline, said over the weekend that it had shut the 622,000 barrel-per-day (bpd) pipeline because of a tar sands oil spill.

The probability of the Keystone spilling tar sands oil, the dirtiest fossil fuel on the planet, was the principal reason why the Biden Administration voted down the expansion of Keystone to transport 830,000 bpd to refineries on the Gulf Coast of Texas at the beginning of its term in office in 2000.

Keystone is the primary artery shipping the crude from Alberta to refiners in the U.S. Midwest and the Gulf Coast, and also sends barrels to the U.S. hub in Cushing, Oklahoma.

The size of the leak, which occurred about 20 miles south of a key junction in Steele City, Nebraska, has been estimated by TC Energy at 14 000 barrels, which would make this the largest in Keystone's history.

U.S. Pipeline And Hazardous Materials Safety Administration (PHMSA) personnel have been deployed to the site to investigate the leak near Washington, Kansas, a town of about 1,000 people.

On 15 November the company announced it would curtail volumes on the pipeline due to some severe weather-related incidents without specifying the size or duration of the curbs.