Fire officials in Toronto say they would support a ban on sky lanterns, the mini hot-air balloons often used for outdoor celebrations and memorials that some provinces have outlawed as a fire risk.

The colourful lanterns, which use the heat of a small flame to gently rise into the sky, have been banned in Nova Scotia, Newfoundland and Prince Edward Island.

The mini lanterns are made of a lightweight, fire-resistant material and are powered by a slow-burning flame, similar to a hot-air balloon. The rising heat of the flame fills up and illuminates the multi-coloured balloons, creating a spectacle popular for weddings, memorials and outdoor celebrations.

The lanterns are designed to safely drift back to earth when their fuel expires and manufactures claim they are biodegradeable.

And while they may make for a pretty sight, some fire officials are worried they could be dangerous.

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Shawn Hamilton said the flying lanterns, which are powered by a slow-burning flame, are popular items in his Toronto store. (CBC)

Toronto District Fire Chief Peter Derrington said he tried one of the lanterns once and didn't like what he saw.

"I realized once it got up, that I had lost control of it and there was a flame burning inside," he said.

Ontario's fire marshal is also concerned and looking into a province-wide ban in light of this summer's dry conditions.

Shawn Hamilton, who sells the lanterns at his party supply store, says they are safe when used properly by an adult.

"We sell hundreds of these," he told CBC News. "Sometimes a client will come in and say 'I want a hundred.' When you see 20 or 30 of them in the sky, it's quite spectacular."

So far the lanterns have not been linked to any fires in Ontario but they have been blamed for starting some fires in the U.K.

For now, Ontario's fire marshal is asking retailers to voluntarily pull them from the shelves.

With files from CBC's Genevieve Tomney