GRAND FORKS — Federal regulators have ordered that the portion of the Keystone pipeline that began leaking in North Dakota last week stay shut down until further notice.

The pipeline, which has leaked more than 383,000 gallons of oil in a field near Edinburg, has been shut down since Oct. 29. A little more than half of the oil has been cleaned up from the spill site, but the cause of the leak has not been determined, according to a company spokesperson.

The order, sent by the U.S. Pipeline and Hazardous Materials Safety Administration on Tuesday, Nov. 5, states that continued operation of the affected pipeline segment would be “hazardous to life, property and the environment without immediate corrective actions.”

“After evaluating the foregoing preliminary findings of fact, I find that the continued operation of the affected segment without corrective measures is or would be hazardous to life, property and the environment,” PHMSA’s associate administrator for pipeline safety, Alan Mayberry, wrote in the order.

Mayberry also pointed to other Keystone spills in recent years.

The pipeline carries crude oil across portions of Canada, the Dakotas and much of the Midwest. The portion of the pipeline section that failed was installed in 2008, according to the order document.

Under the corrective action order, TC Energy is required to shut down the affected segment, develop a restart and return-to-service plan, test the failed pipeline segment in a third-party lab, as well as a number of other tests.

The company also must find the root cause of the leak and submit a report to the PHMSA.

TC Energy says work “continues to progress at the Edinburg incident site with about 200 round-the-clock personnel focused on clean-up and remediation activities.”

“We’re continuing to monitor air quality around the site and the surrounding area throughout clean-up, with no concerns,” the company’s website states.