A crack caused a pipeline rupture leading to a wildfire in west-central Alberta in 2024, as per a report released on Thursday. The Transportation Safety Board of Canada (TSB) revealed findings on the incident involving a natural gas pipeline near Edson, Alta., situated approximately 200 kilometers west of Edmonton.
The report indicated that at around 10:45 a.m. on April 16, 2024, a 36-inch pipeline carrying sweet natural gas ruptured about 36 kilometers northwest of Edson. The pipeline, owned by Nova Gas Transmission Ltd., a subsidiary of TC Energy Corp., suffered stress corrosion cracking due to a combination of soil conditions, degraded protective coating, and increased internal pressure.
Soil testing at the site showed microbiological activity capable of corroding the pipeline’s steel. Additionally, the compromised external coating exposed the steel to external elements, facilitating corrosion. The report highlighted that the pipeline’s pressure was raised to its highest operational level on the morning of the explosion, leading to the crack fully rupturing.
Furthermore, it was revealed that the crack had been detected two years earlier in a 2022 in-line inspection but was classified as non-reportable. Analysts downgraded a potential crack identified at the rupture site to a non-reportable “metal loss” feature, consequently omitting it from TC Energy’s inspection and risk assessment processes.
The TSB emphasized the importance of human performance consistency in identifying pipeline issues to prevent similar incidents. TC Energy pledged to enhance its inspection processes and integrity management practices in response to the report’s findings. Similarly, Baker Hughes expressed commitment to improving its inspection technologies and services based on the TSB report.
The report also disclosed new details about the rupture aftermath, stating that the explosion created a seven-meter-deep crater after the natural gas ignited. Approximately 20 meters of the pipe were expelled due to the explosion, with the largest debris piece launched 200 meters away. The escaping natural gas burned until self-extinguishing at 1:45 p.m. that day, releasing nearly six million cubic meters. The incident triggered a wildfire covering just over 60 hectares but caused no injuries.
The damaged pipeline section was replaced and resumed operation under reduced pressure on May 27, 2024.
