A crack was identified as the cause of a pipeline rupture that triggered a wildfire in west-central Alberta in 2024, according to a report released by the Transportation Safety Board of Canada (TSB) on Thursday. The incident took place near Edson, Alberta, approximately 200 kilometers west of Edmonton.
The report disclosed that on April 16, 2024, at around 10:45 a.m., 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 factors including soil conditions, degraded protective coating, and increased internal pressure.
Soil testing at the site revealed microbiological activity that could corrode the pipeline’s steel. Additionally, the compromised external coating exposed the steel to external elements, leading to potential corrosion. The rupture occurred when the pipeline’s pressure was raised to its highest operating level, causing the crack to fully rupture.
Although a crack had been detected during a 2022 in-line inspection, it was classified as non-reportable by analysts. The TSB highlighted that human error could result in missed identification of pipeline cracks. TC Energy expressed its commitment to enhancing integrity management practices in response to the report’s findings.
Following the rupture, a natural gas explosion created a seven-meter-deep crater, ejecting about 20 meters of the pipe up to 200 meters away. The fire burned until self-extinguishing at 1:45 p.m. on the same day, releasing nearly six million cubic meters of natural gas. The incident led to a wildfire that scorched over 60 hectares but fortunately caused no injuries.
The damaged pipeline section was replaced and resumed operations at reduced pressure on May 27, 2024, after necessary repairs were completed.