NEW YORK • About 5,000 barrels of oil, or about 800,000 litres, gushed out of the Keystone Pipeline earlier this week in South Dakota, blackening a grassy field in the remote north-east part of the state and sending clean-up crews and emergency workers scrambling to the site.
"This is not a little spill from any perspective," said Ms Kim McIntosh, an environmental scientist with the South Dakota Department of Environment and Natural Resources. No livestock or drinking water sources appeared to be threatened, Ms McIntosh said, and no farm buildings or houses were within a mile of the site.
The spill, near Amherst, comes just days before regulators in neighbouring Nebraska decide whether to grant the final permit needed to begin construction on a different pipeline proposal, the Keystone XL, which would be operated by the same company.
An announcement in Nebraska is expected on Monday.
The pipeline company, TransCanada, said in a statement that the South Dakota leak was detected around 6am local time on Thursday. The pipeline was shut down, and the cause of the leak was under investigation.
"TransCanada appreciates the collaborative support of local officials, emergency response personnel and commissioners in Marshall County, as well as the landowner who has given permission to access land for assessment, identification and clean-up activities," the company said in its statement.
A photo of the spill, which was posted
The Keystone Pipeline is part of a 4,324km system that carries crude oil from Alberta to several points in the United States, including Illinois and Oklahoma.
Opponents of Keystone XL, which is proposed to run about 1,770km and would become part of the Keystone system, quickly cited Thursday's spill as evidence of the risks posed by such pipelines, and urged Nebraska regulators to take note.
"We've always said it is not a question of whether a pipeline will spill, but when, and today TransCanada is making our case for us," said Ms Kelly Martin of the Sierra Club. "This is not the first time TransCanada's pipeline has spilled toxic tar sands, and it won't be the last."
Keystone XL has the strong support of President Donald Trump and most Republican politicians, but it has faced years of vocal opposition in Nebraska from some farmers and ranchers who worry that a spill could spoil their groundwater and decimate agricultural land.
Thursday's episode is one of several major pipeline spills in recent years. More than 3.8 million litres leaked from a pipeline into the Kalamazoo River in Michigan in 2010, and about 190,000 litres of oil gushed into the Yellowstone River in Montana in 2015, contaminating drinking water there.
Oil pipelines have faced greater scrutiny since thousands of protesters gathered near the Standing Rock Sioux Reservation in North Dakota last year to protest the Dakota Access Pipeline. The site of Thursday's spill was near the boundaries of the Lake Traverse Reservation, home of the Sisseton Wahpeton Oyate tribe.
Mr Dave Flute, the tribal chairman of the Sisseton Wahpeton Oyate, said he was contacted early in the afternoon by emergency management services and told that there was a "substantial leak" in the pipeline.
"We are monitoring the situation as this leak is adjacent to our reservation," Mr Flute said. "We do not know the impact this has on our environment at this time, but we are aware of the leak."
NYTIMES
