In 2016, about 400 barrels were released from the original Keystone pipe network via leaks, which federal investigators said resulted from a "weld anomaly".
[159]
On November 17, 2017, the pipeline leaked around 9600 barrels
[160] onto farmland near
Amherst, South Dakota. The oil leak is the largest seen from the Keystone pipeline in the state. The leak lasted for several minutes, with no initial reports of damage to water sources or wildlife. Although the spill did not happen on Sioux property, it was in close enough proximity to potentially contaminate the aquifer used for water.
[161][162] The pipeline was immediately shut down,
[163] and TransCanada began using the pipe again 12 days after the leak.
[160] For much of late 2017, the Keystone pipeline operated at reduced pressure during remediation efforts. The federal
Pipeline and Hazardous Materials Safety Administration said that the failure "may have been caused by mechanical damage to the pipeline and coating associated with a weight installed on the pipeline in 2008". Later, the National Transportation Safety Board (NTSB) found that a metal tracked vehicle had run over the area, damaging the pipeline.
[159][164] In April 2018, a federal investigation found that 408,000 gallons of crude had spilled at the site, almost twice what TransCanada had reported. That number made it the seventh-largest onshore oil spill since 2002.
[165][166]
In April 2018,
Reuters reviewed documents that showed that Keystone had "leaked substantially more oil, and more often, in the United States than the company indicated to regulators in risk assessments before operations began in 2010."
[163]
On October 31, 2019, a rupture occurred near
Edinburg, North Dakota, spilling an estimated 9,120 barrels
[167] (383,000 gallons / 1.4 million litres) where the 45,000 gal that were not recovered from the 0.5 acre containment have spread contaminating 5 acres.
[168] This occurred while the South Dakota Water Management Board was in the middle of hearings on whether or not to allow TC Energy to use millions of gallons of water to build camps to house temporary construction workers for Keystone XL construction.
[169]
