Stress corrosion cracking led to 2018 pipeline explosion near Prince George
PRINCE GEORGE, B.C. — The Transportation Safety Board of Canada, in its investigation report released today, found that stress corrosion cracking led to a pipeline rupture and fire northeast of Prince George, on October 9, 2018.
Deficiencies in predicting the extent of cracking of the 36-inch natural gas pipeline operated by Westcoast Energy Inc., and a deferred inspection, led to a hazard being undetected prior to the pipeline rupture.
“The pipeline operator had a stress corrosion cracking hazard management plan in place for this pipeline,” reads the report. “However, the extent of the existing crack growth did not take into account all potential uncertainties in the predicted crack growth. This resulted in cracks growing at higher rates than the model predicted. Additionally, an inspection of this pipeline segment scheduled for 2017 was deferred until the fall of 2018. As such, the existing cracks remained unchecked.”
The report goes on to say that although emergency response activities were successful in mitigating the impacts of the occurrence, the investigation determined that during periodic emergency response exercises in the four years prior to the occurrence, not all nearby communities and operators of nearby pipelines were included.