A fatal blaze that claimed four members of one family in East Gwillimbury last March started in a clothes dryer, according to investigators.

The fire likely started because of a lint buildup in a vent. Without working smoke detectors on the main floor, the fire spread quickly, trapping Kevin and Jennifer Dunsmuir plus two of their sons in a bedroom.

Ontario Fire Marshall Ted Wieclawek said the fire was detected too late for firefighters to attempt a rescue.

East Gwillimbury Mayor Virginia Hackson hopes this underscores the need for working smoke alarms and a fire escape plan.

Fire investigators are also working on a public service announcement to remind people to clean their dryer vents and make sure they are installed properly. The fire in East Gwillimbury is far from the only one. According to the National Fire Protection Association, more than 15,500 fire start in clothes dryers every year in the U.S.

"A lint trap will not stop all of the dryer lint," Paul Capellina of Capps Duct Cleaning Services told CTV Toronto. Lint "is so fine, it will light instantly."

Capellina suggests making sure the duct work is properly installed and empty the lint trap after every load.

"If not clean the lint will build up and eventually more of it will push through," he said. And he suggests that your dryer needs a proper cleaning every three years.