The Keystone pipeline was temporarily shut down on Thursday, after leaking about 210,000 gallons of oil into Marshall County, South Dakota*, during an early-morning spill.
TransCanada, the company which operates the pipeline, said it noticed a loss of pressure in Keystone at about 5:45 a.m. According to a company statement, workers had “completely isolated” the section and “activated emergency procedures” within 15 minutes.
Brian Walsh, a state environmental scientist, told the local station KSFY that TransCanada informed the South Dakota Department of Environment and Natural Resources about the spill by 10:30 a.m.
TransCanada estimates that the pipeline leaked about 5,000 barrels of oil at the site, Walsh said. A barrel holds 42 U.S. gallons of crude oil.
The Keystone pipeline system is nearly 3,000 miles long and links oil fields in Alberta, Canada, to the large crude-trading hubs in Patoka, Illinois, and Cushing, Oklahoma. It was completed in 2011. The entirety of its northern span—which travels through North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, Missouri, and Illinois—would stay closed until the leak was fixed, the company said.
TransCanada said it was still operating the pipeline’s southern span, which connects Oklahoma to export terminals along the Gulf Coast.
The pipeline’s better-known sister project—the Keystone XL pipeline—was proposed in 2008 as a shortcut and enlargement of the Keystone pipeline.
In 2011, climate activists seized upon the Keystone XL pipeline, warning that its completion would allow the exploitation of much of Alberta’s tar sands and lock in too much future carbon pollution. James Hansen, then the director of the NASA Goddard Institute for Space Studies, warned in The New York Times that exporting oil from the Albertan tar sands would mean “game over for the climate.”
In 2015, President Barack Obama blocked the pipeline as part of his administration’s preparation for the UN climate-change talks in Paris. But less than a week after his inauguration, President Donald Trump ordered that decision reversed.
TransCanada faces one final approval—from the Nebraska Public Service Commission—before it can finish building Keystone XL. In a fluke of timing, that all-important meeting will take place this Monday, November 20.
TransCanada has already completed two spans of new pipeline around the trading hub in Oklahoma. Those projects make up about 40 percent of the Keystone XL project, and oil is already flowing through them. But even if the company wins approval next week, some analysts argue that the falling price of oil has made Keystone XL uneconomical.
The long-term environmental costs of an oil spill can vary greatly by location and the length of time the spill goes unnoticed. In 2006, BP spilled 267,000 gallons of crude oil in Prudhoe Bay, on Alaska’s northern coast. Though that is about the same amount that leaked from Keystone on Thursday, it flowed from the BP pipeline over at least five days. BP ultimately paid more than $100 million to the federal government, the state of Alaska, and Alaskans for damages related to the incident.
* This article originally misstated that the spill occurred in North Dakota. We regret the error.