Kansas oil spill was 10 years in the making: investigation

WASHINGTON COUNTY (KSNT) – A third-party investigation into the cause of the largest oil spill in Keystone history in north-central Kansas has been concluded.

On Friday, April 21 TC Energy and the Pipeline and Hazardous Materials Safety Administration (PHMSA) received the findings of Root Cause Failure Analysis (RCFA), a third-party organization, into the Milepost 14 incident that caused hundreds of thousands of oil to spill into Mill Creek. The spill was designated as the largest in the company’s history, dumping 588,000 gallons or 14,000 barrels of oil, before it was contained, according to an Associated Press (AP) report.

“We are unwavering in our commitment to fully remediate the site and are taking action on the recommendations from the RCFA,” said Richard Prior, president, Liquids Pipelines, TC Energy. “We will not stop until we have completed this work. We safely restarted the Keystone System in December 2022 and remain confident in its reliability as we deliver the energy the continent relies on.”

Remediated area of the creek upstream of the Milepost 14 feature site. (Photo Courtesy/TC Energy)

The key findings of the report begin with an analysis of the primary cause of the rupture that led to the spill. The RCFA found that the cause was a “progressive fatigure crack” coming from a girth weld that connected a manufactured elbow fitting to the pipe constructed across Mill Creek. The weld transitioned the pipe wall thickness from the elbow fitting to the adjacent piping and was completed at a fabrication facility. The workmanship of the weld was confirmed to be compliant with codes and standards by the RCFA.

The pipe was weakened due to “Inadvertent bending stresses” that led to a crack developing in the girth weld, according to the RCFA. Bending stresses during construction gave way to a deformation in the elbow fitting and a wrinkle in an adjacent section of piping. The RCFA also said the design of the weld transition made a “stress concentration point,” which made the pipe at this spot open to bending stresses. This resulted in the start of a crack in the weld which led to failure through operations after a decade of time.

The RCFA’s findings line up with a previous investigation that was released in February. The report from RCFA also notes that the Milepost 14 section operated below its temperature and pressure design limits.

TC Energy vowed to implement a plan including the RCFA’s recommendations to make lasting changes in their pipeline integrity program and overall safety performance. Their plans involve excavations to investigate other sites that share similarities with the Milepost 14 segment; performing additional in-line inspections; and reviewing and evolving pipeline design guidelines, construction, operations and integrity management practices.

“We have made significant progress on our remediation and, to date, recovered 98 percent of the released product and cleaned up 90 percent of the Mill Creek shoreline. We are grateful to the agencies and personnel who continue to support this response, including the U.S. Environmental Protection Agency (EPA), the Kansas Department of Health and Environment (KDHE) and approximately 3,000 skilled personnel. Our team has achieved over 1 million person-hours in support of the commitment to this response and the safety of our system.”

At the time of the spill, questions were raised by environmentalists and safety advocates about whether TC Energy should keep a federal government permit to allow the pressure inside parts of its Keystone system to exceed the typical maximum permitted levels. A U.S. Government Accountability Office report from 2022 said there had been 22 previous spills along the Keystone system since it began operation in 2010, with many of them on TC Energy property and fewer than 20 barrels. In total, there was a little less than 12,000 barrels from those 22 events.

The deaths of numerous animals were connected to the spill and two workers were injured during the cleanup process. Kansas lawmakers called for hearings earlier this year to get more information about the spill while conservationists made noise over the environmental impact to the local area and Kansas waterways.

The Associated Press contributed to this report.

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