Cause under investigation after fire rips through vacant south London building

London, Ont. -

London firefighters are investigating the cause of a massive blaze in a vacant factory building at 10 Centre St., just off of Wharncliffe Road South.  

It was eventually brought under control late Tuesday night.

The smoke was so thick and heavy that the city sent has sent out a warning to anyone within one kilometre of the site to keep their doors and windows shut.

“You’ll notice that the smoke is yellow, brown, black, all different colours, so there’s a lot of different things that are burning inside the building,” said Platoon Chief Gary Mosburger. “That kind of smoke produces heavy levels of carbon monoxide, hydrogen, cyanide, things that people should not be breathing in. So we’ve asked people to protect in place, shut off their hvac systems, close their windows, and stay indoors.”

Crews were called to the fire just over the supper hour Tuesday. It roared through the evening with crews working in shifts to knock it down.

“We’re in a defensive strategy fighting the fire from the exterior,” said Mosburger. “The fire itself, it’s just way too dangerous to send firefighters in the interior to a building that we already are aware of that was vacant.”

No one was injured.

Neighbour Warren Martin tells CTV News London individuals are often spotted coming in and out of the building. “Abandoned building and usually there’s a lot of homeless people that live in there. Old mattresses and stuff dragged in and all that.”

The vacant building has been on the city’s radar for some time. Earlier this year it appeared on a list of sites recommended for demolition by city staff.

“Well sometimes you think a lot of these things should be torn down and not just left if it’s a fire trap,” said neigbour Dave Robinson as he watched firefighers work to keep the fire under control.

It had originally been home to Hubson Transport in the 70s but more recently housed a moving company, karate school and renovation company.

The shell of the building was torn down Wednesday, but the cause of the fire remains under investigation.

- With files from CTV News London's Nick Paparella