Gov. Doug Burgum, R-N.D., is urging TC Energy to "review its pipeline inspection and monitoring programs" after a portion of the Keystone Pipeline leaked on Thursday, spilling an estimated 9,120 barrels of oil near Edinburg.

Burgum said he "received assurances" from the Canada-based company that it would continue to "clean up and remediate the site as thoroughly and quickly as possible," according to a statement on Friday.

Although the leak has been contained to the area, about 22,500 square feet of vegetation and soil within the wetland region was affected. Drinking water sources remained unharmed, according to Karl Rockeman, director of North Dakota’s Division of Water Quality.

KEYSTONE PIPELINE LEAKS OIL IN NORTHEASTERN NORTH DAKOTA

“The company has the spill contained and nothing is moving off-site,” State Environmental Quality Chief Dave Glatt said, adding that about 4,200 gallons of crude oil have been recovered.

The pipeline and the roads surrounding it remained closed on Friday and personnel worked to remove the visible oil and affected soil in the area. Workers are also expected to dig up a portion of the $5.2 billion underground pipeline within the next few days to inspect it, as the cause of the spill is still unknown.

The pipeline, which opened in 2011 to transport crude oil across Saskatchewan and Manitoba and through North Dakota, South Dakota, Nebraska, Kansas and Missouri on the way to refineries in Patoka, Ill., and Cushing, Okla., can handle about 23 million gallons a day.

TC Energy said an operations control center detected a drop in pressure at around 10:20 p.m. on Oct. 29 and immediately notified state and federal regulators, including the Pipelines and Hazardous Materials Safety Administration (PHMSA) and the National Response Center (NRC) as they began to shut down the pipeline and contain the spill.

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The Associated Press contributed to this report.