The cause of a fire that consumed an industrial building at Kemp Concrete near Paul Lake Road will remain a mystery for the time being due to safety concerns.

A precariously sagging roof and stressed I-beams kept fire investigators from accessing the remains of the 12-metre by 30-metre mechanical shop on the Chief Louis Way site on Tuesday.

The building was left charred after fire tore through it at around 8 p.m. Sunday.

"Until they can get a structural engineer to deem it safe, we had to back out," Kamloops Fire Rescue fire investigator Dan Funk.

It's unclear whether an investigation will ever happen since Kemp's insurers must determine whether it's worth paying for the work needed to shore up the building or just pay out the claim, said Funk.

For the rest of the site, it's business as usual, he said.

"We taped off the building around the perimeter but the rest of the property's good."

Calls to the company were not returned by press time Tuesday.

An RCMP report on the weekend stated preliminary findings didn't arouse suspicion of arson.

Funk said the industrial site contained several items that could have sparked the fire.

"There's lots of welding going. There's grinding. There's working with oil. There's gasoline storage. There's chemical storage. There's electricity. You name it, it's there."