KITCHENER - Four members of a Kitchener family were taken to hospital with carbon monoxide poisoning early Friday.

Kitchener firefighters responded to a call at about 3 a.m. Friday to a home near Ottawa and Hoffman streets.

Two members of a family called 911 after coming home to discover two other family members unconscious. All four people were taken to hospital for carbon monoxide poisoning. Firefighters had no information about the condition of the family members.

The firefighters' carbon monoxide monitor sounded as soon as they entered the home, said platoon Chief Terry Gitzel. "The CO levels were very high," he said.

Carbon monoxide, which is odourless, colourless and tasteless, can build up to dangerous levels in enclosed spaces where a fuel-burning appliance such as a fireplace or furnace isn't working properly.

The area had suffered a power outage earlier that evening after a car struck a hydro pole, and the family had run a generator in their garage to have power.

Carbon monoxide kills more than 50 people a year in Canada.

Carbon monoxide detectors are mandatory in all homes. The home in Friday's incident had a detector, but it wasn't working.

"We want to remind people that they're required to have a CO monitor," Gitzel said. He stressed it's important to check that both the smoke and carbon monoxide detectors in a home are working.