FREEMAN, S.D. — TransCanada is investigating “visible signs of oil” on a small surface area along its Keystone pipeline right-of-way about four miles from Freeman in southeast South Dakota.

An estimated 210,000 gallons of oil have leaked from the Keystone pipeline in South Dakota, according to TransCanada.

Climate advocates and representatives from the Rosebud Sioux Tribe in South Dakota protest against the Keystone XL pipeline in front of the home of U.S. Senator Mary Landrieu (D-LA), chair of the ...

The oil leak occurs just a few days before Nebraska state regulators will decide on the fate of TransCanada's controversial sister project, the Keystone XL Pipeline.

One of two energy substations near Murdo, South Dakota, meant to power oil pumps down the Keystone XL Pipeline. Both sit nearly completed and unused.

TransCanada Corp. officials say workers have shut down much of its Keystone pipeline after an oil leak in South Dakota.

TransCanada Corp. officials say workers have shut down much of its Keystone pipeline after an oil leak in South Dakota.

TransCanada Corp. officials say workers have shut down much of its Keystone pipeline after an oil leak in South Dakota.