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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Failure Investigation Report - TC Oil Pipeline Operations, Inc.

Friday, October 25, 2024

PHMSA is sharing its Failure Investigation Report following an investigation into TC Oil Operations' December 7, 2022, failure involving its 36-inch Keystone Cushing Extension pipeline rupture in Washington County, Kansas. The failure resulted in an estimated release of 12,937 barrels of crude oil, affecting Mill Creek and other nearby areas. The report outlines PHMSA's findings as part of its investigation into the cause of failure. 

PHMSA takes steps to learn from every major pipeline, liquified natural gas (LNG) or underground natural gas storage (UNGS) event. Based on findings and other relevant information gathered in the course of an investigation, PHMSA will order an operator to take actions to prevent reoccurrence and will advise other operators who may have similar factors—known or unknown—potentially impacting the long-term safe operation of their pipeline assets. Following the Washington County failure, PHMSA issued TC Oil Operations a Corrective Action Order on December 8, 2022, and an Amended Corrective Action Order on March 7, 2023, requiring the operator to take specific actions to ensure the safety of the pipeline and prevent a similar failure from recurring.

PHMSA publishes data for all reportable failures and makes investigation results publicly available at Data and Statistics Overview | PHMSA. PHMSA also uses investigation results to direct the agency's inspection and enforcement resources, issue advisory bulletins, improve regulations, develop and disseminate outreach, improve emergency response readiness, update personnel training, and identify potential research and development projects. 

In addition, all findings—including causal factors deemed to have contributed to an incident as well as any other identified concerns arising from PHMSA's investigation—are incorporated into future PHMSA oversight of an operator and their assets. This can include additional or ongoing checks of operator documentation, site inspections, on site or off-site laboratory analysis, staff interviews, review of operator safety and maintenance procedures, integration of new PHMSA guidance or industry best practices, and more. PHMSA's continued attention to matters raised in its investigations and reviews may continue indefinitely for as long as necessary to ensure public and environmental safety.

For full details, see the Failure Investigation Report in the above link, as well as PHMSA's Corrective Action Orders in the related links section.

**On October 1, 2024, TC Energy and South Bow became separate entities. At the time of this report’s publication, South Bow operates former TC Energy liquid pipeline assets including the failure segment addressed in this report.

DOT is committed to ensuring that information is available in appropriate alternative formats to meet the requirements of persons who have a disability. If you require an alternative version of files provided on this page, please contact PHMSA-Accessibility@dot.gov.