News release

Today, the Transportation Safety Board of Canada (TSB) released its investigation report (P22H0023) into a pipeline rupture that resulted in an explosion and fire near Fox Creek, Alberta.

In the early morning of 07 April 2022, a natural gas pipeline operated by NOVA Gas Transmission Ltd. ruptured. The escaping gas ignited, resulting in a fire that burned a 12 000 m2 area. The fire self-extinguished after the flow of gas was stopped by manually closing isolating valves upstream and downstream of the rupture. There were no injuries and no evacuation was required.

The investigation found that the pipeline ruptured due to reduced pipe wall strength caused by external corrosion. The pipeline’s external coating system had degraded over time, exposing the surface of the pipe to the external soil environment. An impressed current cathodic protection (CP) system was installed to protect the pipe surface from corrosion in the event of degradation or failure of the external coating. In this occurrence, the CP system was not adequately protecting the exposed surface of the pipe as intended.

The pipeline’s proximity to a nearby third-party pipeline, combined with degraded pipe coating, low soil resistivity and an incomplete electrical CP bond, contributed to stray current interference. This led to accelerated external corrosion of the pipeline at the occurrence location.

Currently, there is no centralized system in Canada for consolidating information about pipeline CP system locations and operating characteristics. If pipeline operators are not fully aware of the operating characteristics of third-party CP infrastructure in close proximity to their pipelines, CP effectiveness may be compromised, increasing the risk of corrosion. After the occurrence, NOVA Gas Transmission Ltd. replaced the damaged sections of pipe and initiated steps to permanently shut down the entire pipeline.

See the investigation page for more information.