Three adults are dead and two are in hospital after a suspected case of carbon monoxide poisoning at a Brampton, Ont. home, police said.
Peel Regional Police have identified the victims as a 60-year-old father, 59-year-old mother and their 36-year-old son.
Two other men were transported to hospital. Police said they are also family members, and will survive.
They were found unconscious when the couple's other son, 29, returned to the home at 2 Linden Cres., near Dixie Road and Queen Street, at 1:55 a.m.
The three victims who died were found on the ground floor. The other men were found in the basement, CP24's Cam Woolley reported.
When the son arrived, he noticed that the carbon monoxide detector was sounding.
Firefighters later reported the detected carbon monoxide levels at more than double the fatal dose.
The family's furnace broke on Sunday, police said. They'd been using two portable propane heaters indoors to keep the house warm.
"The propane heaters are what we're looking at as the cause of the believed carbon monoxide poisoning," Const. Fiona Thivierge told reporters on scene.
The chief coroner's office will be conducting autopsies to determine the exact cause of death, but "everything's pointing towards carbon monoxide," Thivierge said.
Police will also be looking at the carbon monoxide alarm to be sure it was functioning properly.
Meanwhile, police are warning the public never to use fossil fuels to heat a home unless it is well-ventilated.
Signs of CO poisoning
Carbon monoxide (CO) is an odourless, colourless gas emitted when fossil fuels such as propane or kerosene are burned.
Early warning signs include:
Carbon monoxide detectors should be installed on every level of a home, especially near bedrooms.
If a detector sounds, the building should be vacated, then residents of the home should call 911. The building should not be entered until an official has resolved the problem.