Pipeline explosion near Prince George might have been prevented by more frequent inspection: TSB

A violent pipeline explosion near Prince George, British Columbia, occurred after the pipeline operator improperly postponed a scheduled hazard management inspection, an investigation by the Transportation Safety Board (TSB) has found.

The 2018 explosion was caused by stress fractures in the line, according to the TSB report. The explosion created a huge fireball and forced more than 100 people to evacuate their homes. In addition, the damage to the pipeline cut off natural gas supplies across the province and to the United States for months.

The report, released Wednesday, found that the danger of the 2018 explosion at Shelley, British Columbia, went undetected because the operator, a subsidiary of Enbridge, postponed an inspection for several months before the explosion.

“It's mind-boggling,” said Malcolm Macpherson, legal counsel for the Lheidli T'enneh First Nation, the community closest to the explosion. “It was downright frightening to read. There were some very serious breaches of safety protocols identified by the Transportation Safety Board that are certainly not what you would expect from a top-notch pipeline operator.”

“You might expect that in a third world country, but not in Canada,” Macpherson said.

Lheidli boss Dayi Clayton Poutney described the security breaches as “unacceptable”.

“Our concern is for the safety of our members and other people who live near pipelines,” Poutney said.

Enbridge is now apologizing to the people who fled their homes after the explosion.

“We know this incident has caused great concern and impacted the lives of many people in the region,” Enbridge Vice President Michele Harradence said Wednesday morning. “We sincerely apologize for this. We have learned from this incident and have taken steps to ensure the safety of our natural gas system.”

But this safety measure came too late to reduce the risk of explosion.

A senior pipeline investigator with the TSB said there is a specific process in place for companies seeking to postpone inspections. They must determine the requirements for the postponement, conduct an engineering assessment to ensure the postponement is safe and obtain appropriate permits.

“In this case, we found that the postponement occurred without these issues being properly addressed,” Jennifer Philopoulos told CBC.

When the 91-centimeter-thick Enbridge pipeline burst and caught fire on October 9, 2018, no one was injured. However, more than 100 people living within a two-kilometer radius left their homes as a precaution.

WATCH | Video of the fire by Terry Teegee, Regional Chief of the BC Assembly of First Nations:

Pipeline explosion sparks massive fire near Prince George, BC in 2018

On October 9, 2018, a pipeline explosion near Prince George, BC, sparked a fireball. A later investigation found that the explosion was caused by stress cracks in a portion of the line.

The amount of natural gas flowing through the province also dropped after Enbridge suspended transport over the ruptured line and a neighboring 76-centimetre-thick line. British Columbians were temporarily asked to avoid “non-essential” use of natural gas, with utility FortisBC receiving only 40 per cent of its usual gas flow.

Analysts later estimated that the explosion had disrupted about 10 percent of daily natural gas production in Western Canada.

People living several kilometers from the blast site reported hearing a thunderous boom from the explosion before looking out their windows to see a huge orange fireball in the sky. The force of the explosion shook windows and covered nearby houses in the Lheidli T'enneh reserve with ash.

The TSB's subsequent months-long investigation revealed that the outer surface of the pipeline section in question was already riddled with stress corrosion cracks before the explosion.

The polyethylene tape used to coat the outside of the pipeline had also come off over time because it was peeling off the metal surface and moisture from the surrounding soil was able to corrode the pipe walls.

The cracks grew larger over time, reducing the capacity of the pipeline as it continued to operate below normal operating levels.

The pipeline was operated by Westcoast Energy Inc., a subsidiary of Enbridge. The TSB said that while Westcoast had a hazard management plan in place to monitor the line for stress corrosion, the extent of the problem in the section that exploded had “not been identified.”

“The model used to predict crack growth did not account for all potential uncertainties in the predicted crack growth. This resulted in cracks growing faster than predicted by the model,” the report said.

As underground cracks continued to grow at a critical rate, Westcoast postponed an inspection of the pipeline scheduled for 2017 until fall 2018.

“As a result, the existing cracks remained undetected,” the TSB explained.

The explosion tore a crater in the ground and burned surrounding trees, the report said. The hole in the ground was about 35 meters long, 13 meters wide and about nine meters deep at the top.

The explosion crater was about 35 meters long, 13 meters wide and about nine meters deep. Several surrounding trees were also burned. (Transportation Safety Board)

On Wednesday, an Enbridge senior vice president said the company was aware of the risk of stress corrosion cracking.

“This is a known threat to the integrity of the pipeline … it has been identified and monitored,” Michele Harradence told CBC's Daybreak North on Wednesday.

“In this case, the cracks grew faster than expected, even though we used the best technology available at the time to inspect the pipeline.”

The Transportation Safety Board was called in to investigate because the agency investigates all incidents involving federally regulated transportation equipment. Pipelines are subject to federal regulation and are a means of transporting goods, although pipeline-related TSB inspections are relatively rare.

The board said it sent Enbridge a pipeline safety alert on June 26, 2019, as part of the investigation. The notice said the company “may wish to review its approach to stress corrosion on at-risk pipelines.”

The TSB said the company has since changed its method for determining the time between inspections and modelling the rate at which stress cracks can grow, and has shortened the maximum time between inspections.

The Royal Canadian Mounted Police (RCMP) of Prince George responded to the explosion on October 9, 2018. Officials confirmed that no one was injured in the explosion. (Andrew Kurjata/CBC)

Harradence said Enbridge now has a “much more aggressive” inspection program, but did not provide an inspection plan.

“Significant parts of our entire BC system… virtually the entire system has been re-examined,” she said.

The TSB said Enbridge had also implemented clearer expectations for emergency drills after the report found that “adjacent communities and operators of nearby pipelines” were not included in previous drills conducted by the company.

The Lheidli T'enneh First Nation claims Enbridge does not have an effective emergency plan for at-risk members. In February 2019, Chief Dominic Frederick said there has been little communication between the First Nation and Enbridge since the explosion. A lawsuit filed by the Lheidli against Enbridge over the pipeline explosion is ongoing.