Firefighters responded to a blaze overnight at an abandoned home in Markham, where another home exploded nearby earlier in the week.
The house caught on fire at about midnight, closing the Donald Cousens Parkway at Highway 7.
No injuries were reported.
On Tuesday, a home in the same area exploded, damaging three other houses.
Police are investigating witness accounts that a man was seen fleeing the scene.
The roofs of the houses on either side of the residence were also damaged.
