Husky Energy says shifting ground is to blame for a pipeline burst in July that leaked crude oil into the North Saskatchewan River and jeopardized the drinking water of thousands downstream.
“The break was a sudden, one-time event in a section of the pipe that had buckled due to the force of ground movement,” Husky said in a summary of a detailed report released Thursday.
FULL COVERAGE: North Saskatchewan River Husky oil spill
The break, which happened about 160 metres from the riverbank, spewed out about 225,000 litres of heavy crude oil and diluent with about 40 per cent of the liquid flowing into the river.
The report by Stantec Inc. found that major rainfall, poor drainage, and a weak clay foundation were likely the causes for the ground movement, though Husky said a 1997 third-party geotechnical assessment showed the area was inactive.
The incident forced the Saskatchewan cities of North Battleford, Prince Albert and Melfort to shut off their water intakes from the river and find other water sources for almost two months.
Husky said it has spent about $90 million responding to the spill, and wrapped up shoreline clean-up efforts in October after recovering about 210,000 litres of what spilled.
The company said other activities taking place on the pipeline system at the time made it more likely to detect false alarms and therefore harder to detect actual spills, but that its investigation found “operators responded appropriately to the data being observed and took proper steps to investigate.”
The company said it first detected anomalies on the pipeline at 8 p.m. on July 20, but didn’t shut down the pipeline until 6 a.m. the next morning.
It said it is reviewing its leak detection processes, and will create defined time periods for diagnostic analysis before moving to a mandatory pipeline shutdown.
Saskatchewan Energy Minister Dustin Duncan says the government will need time to review Husky’s report on the spill as part of the province’s own investigation, which is expected to report early next year.
“This is Husky’s conclusion, and the work that they’ve done as a part of their investigation, that it was ground movement,” said Duncan at the legislature in Regina.
“It’s consistent with what our ministry officials believe to this point, but again, that doesn’t preclude from our final report saying something different.”
The minister said it was too soon to speculate on whether Husky will face charges for the spill, and wouldn’t say how the information could affect pipeline regulations in the future.
“We’re going to have to look at, as a part of not only the outcome of this report but going forward, what we need to do, if anything, to give assurances to the public that there aren’t further risks out there going forward.”
In September, the Ministry of the Economy launched a province-wide inspection of all oil pipelines that cross Saskatchewan rivers or lakes where a potential failure could pose a threat to municipal water supplies.
Duncan said inspection work so far has not raised any concerns about ground instability near shorelines but that the work continues.
With files from Jennifer Graham in Regina