TransCanada Corp. said Saturday that it has completed repairs to its Keystone Pipeline, a week after the pipeline oozed thousands of gallons of Canadian crude into a South Dakota field.

James Millar, a spokesman for the Calgary-based company, said the pipeline was expected to be restarted on Saturday. It’s still not clear what caused a breech.

"We don’t know yet," said Millar, who would only describe the pipeline failure as a "small leak." "We are still working to determine what caused it."

TransCanada has estimated 16,800 gallons, or about 400 barrels of oil, leaked. The company said there was no significant environmental impact or threat to public safety.

Millar said it was the first such breech of the 36-inch steel pipeline since it began operating in June 2010. It has since transported some 1.3 billion barrels of crude from Alberta, Canada, to refineries in Illinois and Cushing, Oklahoma, passing through the eastern Dakotas, Nebraska, Kansas and Missouri.

The Keystone pipeline can handle 550,000 barrels, or about 23 million gallons, daily. It’s part of a pipeline system that also would have included the Keystone XL pipeline had President Barack Obama not rejected that project last November.

TransCanada said Friday that it has received conditional approval from the federal Pipeline and Hazardous Materials Administration to the restart the pipeline after identifying the source of the leak that occurred about 4 miles from the Freeman pump station in Hutchinson County, South Dakota.

The pipeline had been shut down since April. 2. About 100 workers have been working at the site, where crews excavated soil to expose more than 275 feet of pipe to find the leak, the company said.

The company has not released estimates on cleanup costs and repairs.

The recent breech is similar in size to a 2011 spill caused by a faulty valve at a pumping station in North Dakota’s Sargent County. North Dakota health officials said at the time most of the 400-barrel spill was contained by a berm around the pumping station but some oil mist had to be cleaned from standing water in a nearby field.

(Copyright (c) 2016 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)

Join our Newsletter for the latest news right to your inbox