CALGARY, Alberta — February 13, 2026 — Leads & Copy — South Bow Corp. and the Pipeline and Hazardous Materials Safety Administration (PHMSA) have received the independent third-party root cause analysis (RCA) of the incident that occurred at Milepost 171 (MP-171) of the Keystone Pipeline on April 8, 2025, near Fort Ransom, N.D.
The RCA determined the characteristics of the MP-171 incident were unique. The pipe and welds met industry standards, and the pipeline operated within its design pressure. The failure resulted from a fatigue crack along the pipe’s long-seam weld.
According to the RCA, the seam weld geometry was a primary contributor to the failure, leading to a stress concentration that likely initiated the crack during transportation from the pipe mill, before construction and subsequent operations. The presence of hydrogen contributed to material brittleness and increased the growth rate of the fatigue crack, which developed during normal operations spanning 15 years.
Multiple in-line inspections had previously been completed on the section of pipe, including three generations of ultrasonic shear wave technology from two different vendors.
The RCA is available on PHMSA’s website.
South Bow is implementing remedial measures and enhancements across its systems to prevent future incidents. The company has completed seven in-line inspection runs and 51 integrity digs to date, with preliminary results indicating no injurious issues. The in-line inspection process has been modified to address known tool limitations.
South Bow will continue to work with its in-line inspection technology vendors to advance tool performance and validation, address and resolve tool limitations, and develop new technologies. Additional in-line inspection tool runs and integrity digs are scheduled for 2026 as part of South Bow’s program.
As part of PHMSA’s Corrective Action Order (CAO), South Bow has submitted its remedial work plan to the regulator for approval. The plan includes corrective actions already completed and addresses RCA recommendations. Findings from remedial work will be incorporated into the plan and the Company’s programs.
South Bow safely operates 4,900 kilometers (3,045 miles) of crude oil pipeline infrastructure, connecting Alberta crude oil supplies to U.S. refining markets in Illinois, Oklahoma, and the U.S. Gulf Coast.
South Bow’s common shares trade on the Toronto Stock Exchange and the New York Stock Exchange under the symbol SOBO.
“This was a complex set of unique circumstances. We are committed to learning from this incident and are already implementing remedial measures and enhancements across our systems to prevent future incidents,” said Bevin Wirzba, South Bow’s chief executive officer. “I am grateful to our team for their swift and thoughtful actions during the incident response and cleanup efforts, and for their respectful engagement with the community.”
South Bow is committed to maintaining transparency with its regulators, customers, and industry peers throughout this process.
Source: South Bow
