A crack caused a pipeline rupture leading to a wildfire in west-central Alberta in 2024, according to a report unveiled on Thursday by the Transportation Safety Board of Canada (TSB). The incident occurred on April 16, 2024, when a 36-inch natural gas pipeline owned by Nova Gas Transmission Ltd., a subsidiary of TC Energy Corp., ruptured around 36 kilometers northwest of Edson, Alberta. The investigation attributed the rupture to stress corrosion cracking due to a combination of soil conditions, degraded protective coating, and heightened internal pressure.
The report highlighted that soil testing revealed microbiological activity capable of corroding the pipeline’s steel, while the compromised external coating exposed the steel to the environment, facilitating corrosion. The pipeline’s pressure was raised to its maximum operating level on the day of the explosion, causing the crack to rupture entirely.
Notably, the report mentioned that the crack leading to the rupture was detected in a 2022 inspection but was categorized as non-reportable. Despite being identified, the crack was downgraded to a non-reportable classification, leading to its exclusion from TC Energy’s inspection and risk assessment processes. TC Energy expressed its commitment to enhancing integrity and safety practices in response to the incident.
The report also provided new insights into the aftermath, indicating that the explosion created a seven-meter-deep crater and ejected approximately 20 meters of the pipe. The escaping natural gas ignited, resulting in a fire that burned over 60 hectares but caused no injuries. Following the incident, the ruptured pipeline section was replaced and reintroduced with reduced operational pressure on May 27, 2024.