Fire ripped through a home near Yonge Street on Clark Avenue in Thornhill Monday afternoon, destroying much of the structure.

A grandmother, her four grandchildren and another adult were home when the fire started at around 3 p.m., but were able to safely get out of the house.

A witness told CP24 that the home exploded into flames.

“I was in my apartment and I looked out my window and I heard three large blasts,” the witness said.

Police also said that a loud explosion was reported, which may have caused the blaze.

Shortly before 3:30 p.m., police reported that the home was fully engulfed in flames.

Markham fire dispatched six trucks to the scene.

A tree beside the home and a vehicle in the driveway also caught fire, police said.

Neighbours immediately beside the fire were told to leave their homes, said police Staff Sgt. Allen Bonner.

“I believe the neighbours immediately on either side of the house have been evacuated from their residences,” said Staff Sgt. Alan Bonner.

Two firefighters had to be treated by paramedics for suspected heat exhaustion.

Firefighters had the blaze mostly extinguished before 5 p.m. and investigators were expected to take over.