The explosion happened around 1:45 p.m. PT after the woman driver turned on the ignition, sparking the blast.She was taken to hospital with superficial burns.
Fire officials are warning people to properly store their fuel tanks.
"If the vehicle was involved in a motor vehicle accident, [there is] the potential there for a catastrophic fire event on the highway if the containers ruptured," said Port Moody Deputy Fire Chief Gord Parker.
Chuck Morris witnessed the explosion as he was leaving the fast food outlet.
"There was a white panel van with the roof blown right off, there was fire coming out the back, and that's when I noticed a girl trying to pull her way out of the passenger side of the vehicle," he said.
Morris said the victim was badly burned on her face and her hair was melted, but she was conscious immediately after the blast.
Business owner David Albert said his building nearby shook from the explosion.
"Just looking at the van right now, it's amazing that anybody would live though this. It is that destroyed," said Albert.
Earlier reports that two women were in the van at the time of the explosion turned out to be incorrect.