A problem at Petro-Canada's refinery near Edmonton has led to gas shortages or pumps running dry at as many as 90 Petro-Canada and independent stations in B.C. and Alberta, CBC News has learned.

The Calgary-based company is still scrambling to fix a catalytic cracking unit necessary to refine fuel at the facility that broke earlier this month, said Petro-Canada spokeswoman Kelli Stevens.

Stevens said about 120 people are working on the problem to get it repaired at any given time, but the company's best hope is that the refinery is up and running in a week.

Calgary gas bar owner John Balanazario said he and other station owners have been forced to offer higher grade fuels at lower grade prices and absorb the losses out of their own pockets.

"It's bad for business, but good for the customers," he said.

Customer Bell Ainsworth said she can't understand why there is no regular gas left at the pump in the oil-rich province.

"We produce it here," she told CBC News. "Why are we running out?"

The company will face off Thursday in a conference call with angry independent gas station owners demanding compensation to make up for their growing losses.

But Petro-Canada could take a long-term hit if shortages drag on, said Mike Percy, dean of the University of Alberta School of Business.

"People may switch," Percy told CBC News. "Whether they switch in the long term, it depends on the convenience of the particular Petro-Canada station."