Firefighters were called to a senior citizens complex in Unionville, Ont. Monday after a blaze broke out in the complex that forced the evacuation of residents.

No one was injured in the fire but 16 units in the complex were affected by the fire in the Main Street and Highway 7 area, near the Markham-Stouffville Hospital.

About 100 residents were reportedly evacuated from the building.

When the fire started it seemed to be just a lot of smoke but it quickly grew to become an inferno.

Two women out for an afternoon stroll found themselves at the centre of rescue efforts even before Markham firefighters arrived on the scene.

Heather McGilvery and Kathleen Heslip started knocking on doors, telling people to get out. The duo even went into some homes, helping people leave as the flames spread in the roof above them.

"Within seconds the roof was totally on fire."

Their efforts gave residents enough time to escape safely.

But for family members of the residents there were heart-stopping moments as they rushed to the scene, looking for parents, grandparents and more. Seeing the damage, they were relieved to learn that everyone was accounted for an unhurt.

With their homes destroyed, however, a group of seniors will be looking for a place to live and thinking about the memories lost in the flames.

"We're all older and all the little treasures is all we have," one woman told CTV News.

What sparked the blaze is not yet known. But firefighters managed to save many more homes by cutting a trench in the roof of a home that was not on fire. The technique stopped the blaze from spreading.

All the people left homeless have found accommodations for the night.

With a report from CTV's Tom Hayes