This Petro-Canada station in Edmonton, showing only zeros for the price, is one of about a dozen in Alberta and B.C. that have run out of fuel. This Petro-Canada station in Edmonton, showing only zeros for the price, is one of about a dozen in Alberta and B.C. that have run out of fuel. (CBC)

About a dozen Petro-Canada gas stations in Alberta and B.C. have run dry and others are running out, the company said Tuesday.

A catalytic cracking unit in a Petro-Canada refinery in Edmonton suffered a malfunction and had to be shut down last week, said spokesman Jon Hamilton. The facility processes 135,000 barrels of crude oil a day.

"That's kind of the finishing unit for gas at the plant. It's kind of like running a doughnut factory without a deep fryer. We just can't produce product right now," he said.

He said drivers will know if a station is out of gas if they see its price sign with only zeros on it. As well, Petro-Canada will be offering supreme gas at regular price where supplies of regular have run out.

Hamilton said the Calgary-based company is shipping fuel in from across Canada and internationally, but acknowledges customers will be going to Petro-Canada's competitors.

Petro-Canada's refinery in Edmonton suffered a malfunction last week, forcing the company to shut it down for repairs.Petro-Canada's refinery in Edmonton suffered a malfunction last week, forcing the company to shut it down for repairs. (CBC)

"People are somewhat brand loyal, but people tend to look for the lower price, so at this point another factor in their decision-making may be 'Well, they have gas, and they don't,' so they'll go there," he said.

Stations that provide fuel to essential services and independent gas stations that buy their gasoline from Petro-Canada will be serviced before the company's own sites, Hamilton said.

The shortage does not affect supplies of diesel or jet fuel in Western Canada.

In March, a shutdown at Imperial Oil's Strathcona refinery near Edmonton caused gas shortages at Esso stations in Alberta, Saskatchewan, B.C. and Manitoba.

In November, a fire at a Shell refinery east of Edmonton caused a shortage of diesel fuel in Alberta.

Last year, Ontario experienced similar gasoline shortages for several weeks after a fire at Imperial's Nanticoke refinery.

With files from Canadian Press