Paul Flemming, who is also the city's fire prevention officer, said uncertified electrical appliances and cords are becoming more common.
"We're on the constant lookout for Christmas lights and things that are uncertified," he said. "We do have occasions when they caused fires.
Flemming said fire officials check stores regularly for these items, and remove any products they find from the shelves.
He urges shoppers to look for ULC or CSA tags on a product's electrical cord, which shows that it is certified by the Underwriter Laboratories of Canada or Canadian Standards Association.
If there's no tag, Flemming said, don't use that product.
"If you can buy a set of lights for $2, you know there's something not right there," he said.