Emergency crews were at a townhouse fire on Arbour Glen Crescent early Thursday.
A neighbour called 911 just before midnight about smoke coming from one of the middle units in a row of townhouses.
One adult and one dog were found dead inside the building.
Fire officials have since determined there were no working smoke alarms in the unit.
Platoon chief Kirk Loveland said had there been one, it could have made a difference.
“The occupants would have been aware of the fire much earlier before it progressed and would have had a much greater probability of exiting safely,” Loveland said.
“We always state to just get outside and be safe and not to worry about any of the material things in the residency because they are all replaceable, but people aren’t.”
On Thursday Platoon chief Colin Shewell said crews arrived on scene to a smoky fire, that was not very noticeable from the outside.
“Crews encountered heavy smoke and high heat in the unit itself. There was some smoke migration into neighbouring units but those families were able to stay there overnight,” Shewell said.
London police and the Ontario’s Office of the Fire Marshal are investigating at the scene.
Damage is estimated at around $250,000.
“Our condolence goes out to the family that is affected by the tragic fire,” said Shewell
The cause of the fire is still under investigation.
Shewell said fire crews had no issues accessing nearby fire hydrants, as someone had cleared the snow away prior to their arrival — something the department had been encouraging since the weekend’s snowfall.