Several businesses were gutted by a massive fire that ripped through a city block in downtown Nanaimo Wednesday night.

City officials say a heritage building on Commercial Street at Terminal Avenue, the former site of Acme restaurant, is a total write-off.

“It was a great building for this area and downtown,” said Acting Nanaimo Mayor Jerry Hong. “The redevelopment of downtown was a key aspect and having these businesses gone is a really big setback for the city.”

Multiple roads in the area including a stretch of the Trans-Canada Highway remained shut down Thursday morning as crews worked to eliminate hot spots.

Investigators were expected to sift through the wreckage to try to determine where the fire was sparked and what caused it.

“Given the length of time, the amount of water and the fire that has been going on, that complex will probably be a loss,” said Nanaimo’s emergency program manager Karen Lindsay.

No one was in the building and no one was injured after fire broke out around 6:30 p.m. Wednesday, the city said.

Neighbours had to be evacuated from nearby buildings because of dense, heavy smoke that blanketed the downtown core.

Video and pictures of the out-of-control blaze poured in on social media as crews worked to contain it.

A video posted to Instagram shows a powerful backdraft erupt from Fast Frames, a framing business on another side of the building.

All hands were on deck as additional firefighters were called in from neighbouring districts and at least two aerial trucks were deployed.

The battle lasted much of the night and the blaze was under control by early Thursday morning.

The cause of the fire remains under investigation.

With files from the Canadian Press