Investigators are working to pinpoint the cause of a two-alarm blaze that broke out Saturday morning at a building at Dupont Street and Dovercourt Road.

Firefighters were called to the scene around 10 a.m. The flames were extinguished by 10:30 a.m.

It’s unclear what sparked the blaze, which firefighters believe began in a furniture manufacturing area on the first floor. The Ontario Fire Marshal’s office has been called in to investigate.

No one was injured in the fire.

During an initial investigation, officials uncovered a marijuana grow-op in the building’s basement, police said. Police say a resident living in the basement had a license to grow up to 88 marijuana plants, but the number of plants on site was allegedly more than triple the limit.

“It’s quite, quite thick down there, like a little forest,” Sgt. Rob Hargan told CTV Toronto.

In addition, fire officials say the building was not up to code.

“[There was] no sprinkler, no suppression whatsoever, no fire extinguishers, the alarm systems aren't adequate,” said Platoon Chief Trevor Trotter.

A tenant allegedly living illegally on the third floor will have to find new lodging as the building is being closed down, authorities said.

The Toronto Police major crime unit is expected to continue the investigation into the grow-op.