A mother and her three sons have been sent to hospital after a fire broke out at a home in Victoria Harbour, just north of Barrie.
Emergency crews were called to the scene on Nielson Road around 11:30 p.m. on Monday.
OPP Sgt. Peter Leon said a 17-year-old boy was rushed to hospital with life-threatening injuries.
A seven-year-old boy and an 11-year-old boy also suffered serious injuries.
The 44-year-old mother’s injuries are also considered serious.
The fire allegedly started in a Christmas tree.
An investigation into the fire is underway.