TORONTO –  An improperly vented clothes dryer and the lack of a smoke detector on the main floor of a home were the factors that led to a fatal fire that killed a family of four in a small Ontario town north of Toronto last March.

“We were able to identify that the spread, fire, and smoke was sufficiently quick enough that by the time the second floor smoke alarm activated, the occupants were trapped,” said Ontario Fire Marshal Ted Wieclawek during a press conference Wednesday morning.

A final report from the Office of the Fire Marshal revealed that the lack of an alarm on the main floor caused the delay in the fire department response time in the early morning hours of March 29, 2013.

A timeline from the report showed the East Gwillimbury volunteer fire service took 12 minutes  to arrive on scene after the initial 9-1-1 call.

“Due to delay in detection — the fire notification, the response time was not an…