A report released on Thursday revealed that a 2024 wildfire in west-central Alberta was triggered by a pipeline rupture caused by a crack. The Transportation Safety Board of Canada (TSB) disclosed its findings regarding the rupture of a natural gas pipeline near Edson, Alberta, which is situated approximately 200 kilometers west of Edmonton.
According to the report, 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 indicated microbiological activity capable of corroding the pipeline’s steel. Additionally, the compromised external coating exposed the steel to environmental elements, facilitating corrosion. The report highlighted that on the day of the incident, the pipeline’s pressure was raised to its highest operating level, causing the crack to rupture completely.
The TSB mentioned that the crack leading to the rupture had been identified during a 2022 in-line inspection but was deemed non-reportable by analysts. Despite being downgraded to a non-reportable classification, the crack was not considered in TC Energy’s inspection and risk assessment processes.
TC Energy expressed its commitment to collaborating with in-line inspection vendors to enhance their processes and improve integrity management practices. Baker Hughes, the inspection service provider, acknowledged the seriousness of the TSB report’s findings and pledged to enhance inspection technologies and services.
The report also provided new insights into the aftermath of the rupture and subsequent wildfire. Following the rupture, the ignited natural gas caused an explosion, resulting in a seven-meter-deep crater. Approximately 20 meters of the pipeline was ejected by the explosion, with the largest debris piece thrown 200 meters away. The escaping gas burned until self-extinguishing at 1:45 p.m., releasing nearly six million cubic meters of natural gas and sparking a wildfire that burned over 60 hectares.
The damaged pipeline section was replaced and resumed service at reduced operating pressure on May 27, 2024.
