A leak in the Keystone Pipeline has released an estimated 383,000 gallons of oil - about the size of an Olympic swimming pool - into the North Dakota wetlands. The leak is the second leak in two years in the 2,600 mile long pipeline, which carries oil from Alberta, Canada, all the way down to southern Texas.

The pipeline, which is operated by TC Energy, is less than 10 years old.

Karl Rockeman of the North Dakota Department of Environmental Quality told the Associated Press that the spill did not affect any sources of drinking water and TC Energy said in a written statement that no people or animals were harmed.

In 2017, the pipeline leaked over 400,000 gallons of oil across a swath of agricultural land in South Dakota.

The spill occurred as the US State Department is collecting public comments on the Keystone XL expansion in the Keystone Pipeline that would run through Montana, Nebraska, and South Dakota, crossing several tribal lands in the process. The Keystone XL has been the subject of ongoing protests by environmental activists and members of tribal nations whose land the proposed pipeline would cross.

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President Barack Obama killed the Keystone XL deal in 2015, but President Donald Trump authorised the Keystone XL expansion 2017. The measure was blocked by a judge in 2018 for not providing a reasoned analysis justifying the project and its possible environmental impact.

For activists who oppose the Keystone XL pipeline, this latest spill is further proof that it would have serious environmental consequences.