Keystone Pipeline Ordered to Lower Pressure

By Gordon Hopkins The U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration (PHMSA) has ordered TC Energy, the company formerly known as TransCanada Corporation, to reduce the pressure in more than 1,000 miles of the Keystone Pipeline.This order is in response to the oil leak which dumped an estimated 12,937 barrels of crude oil into Mill Creek, three miles east of Washington, Kansas, and approximately 20 miles south of Steele City, on December 7, 2022.The 2,687-mile Keystone Pipeline System transports up to 622,000 barrels of crude oil from Alberta, Canada, to the Midwest and the Gulf Coast. The Steele City facility is a key junction for the pipeline.An Amended Corrective Action Order was issued on Tuesday, March 7, 2023, and states, in part, “The Cushing Extension begins in Steele City, Nebraska and goes to Cushing, Oklahoma, and is approximately 291 miles long. The maximum operating pressure (MOP) of both pipelines is 1,440 pounds per square inch gauge (psig), and they operate under special permit PHMSA-2006-26617.” PHMSA requires that the pressure be reduced, “TC Oil must continue to reduce the operating pressure along the length of the Affected Segment to the previously agreed upon 923 psig limit.”Cause of the LeakOn Thursday, February 9 of this year, TC Energy released the initial findings of an investigation into the cause of the leak, blaming the failure on a weld flaw and bending stress, “We have advanced our root cause investigation with the completion of an independent mechanical and metallurgical analysis of the failed pipe. The analysis concludes that the failure occurred due to a combination of factors, including bending stress on the pipe and a weld flaw at a pipe to fitting girth weld that was completed at a fabrication facility.”TC Energy also noted, “The metallurgical analysis identified no issues with the strength or material properties of the pipe or manufactured fitting. The pipeline was operating within its operational design and within the pipeline design maximum operating pressure.”Pressure Within the PipelineThe Amended Corrective Action Order requires, “operating pressure on the rest of the pipeline extension from Steele City, Nebraska to the Cushing storage hub in Oklahoma and on the entire 1,025-mile main line from the Canadian border to refineries in Illinois, must not exceed 72 percent of the specified minimum yield strength.”On April 30, 2007, PHMSA issued a “Special Permit” to the company to allow a portion of the pipeline to operate at a higher pressure of 80 percent of specified minimum yield strength (SMYS). Without this permit, operating pressure should have been no greater than 72 percent of SMYS.According to the permit, “PHMSA finds that granting this special permit to Keystone to operate two new crude oil pipelines at a pressure corresponding to a hoop stress of up to 80 percent SMYS is not inconsistent with pipeline safety. Doing so will provide a level of safety equal to, or greater than, that which would be provided if the pipelines were operated under existing regulations.”When ask what pressure the pipeline was operating at when the failure occurred, TC Energy responded to FJN, “At the time of the incident, the pipeline was operating within its operational design and permit. We will not comment further on this matter as the incident remains under investigation and anything further would be speculative. We are progressing the root cause analysis.”

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