B.C. could be feeling the effects of last week's natural gas pipeline explosion much longer than previously revealed.

The province's natural gas utility, FortisBC, now says it could be months — rather than weeks — before the end of voluntary natural gas rationing.

And it says there could be an impact on some B.C. industries through to Christmas and New Year's. It's not clear just how many jobs could be affected.

FortisBC vice-president Doug Stout says it all depends on how many cold snaps occur before the main Enbridge pipeline is repaired.

Doug Stout of Fortis B.C. says school might close rather than turning off heat to people's homes.

"Typically, if it starts to get colder and people need to keep some heat on, then we'll go back to curtailing or reducing volumes to industrial customers on the system, which is what we do first," says Stout.

"We'll see how cold the winter gets this year and see if we have to work through a few sticky days, maybe through the middle of winter."

Explosion still unexplained

Last Tuesday's still-unexplained explosion 13.5 kilometres north of Prince George severed the main 36 inch (91 cm) natural gas pipeline in the province, operated by Enbridge Inc.

The Transportation Safety Board is investigating. The RCMP have said the explosion "was not criminal in nature."

Given the mystery, a secondary, parallel 30-inch (76-cm) line was depressurized by Enbridge as a precaution.

On Thursday, after clearance from the National Energy Board, Enbridge re-started the secondary line, but only at 80 per cent capacity as an added safety measure.

That means overall, FortisBC has just 40 to 45 per cent of the natural gas that was flowing into the province before the rupture.

As for the main line, Enbridge says it could be a few days before a road for repair crews is built into the remote area and it has no timeline for completing the job.

"We are still working on that," says Michele Harradence, senior vice-president of Enbridge's gas transmission operations. "We're hoping to measure that in weeks rather than months, but we really won't know for a few more days."

Michele Harradence, Enbridge's Senior Vice-president of gas transmission operations says she doesn't have a timeline for the main 36 inch pipeline to be repaired. (Enbridge)

But even if repairs are completed quickly, she says that doesn't mean both pipelines will be fully operational.

"It could be many months before it returns to full capacity," says Harradence. "It's very important to us that we find out what happened here before we return the pipelines to full capacity."

'May ... have to curtail certain industrial customers'

Shortly after the blast, FortisBC appealed to Lower Mainland residents, universities and industry to voluntarily cut back natural gas consumption.

That helped reduce demand by 20 per cent.

Industrial customers remain under restrictions and that's likely to continue.

"[There] may be some times when we will have to curtail certain industrial customers through this winter," says Stout.

And besides colleges, universities and recreation centres, schools could also be forced to reduce natural gas consumption, perhaps forcing closures.

"Like a snow day," says Stout. "Kids can stay home from school if they have to, as opposed to turning off people's homes and businesses."

"I'd say over the next few months, we're going to be careful with things."

Read more from CBC British Columbia