Nine people have been taken to hospital after exhibiting signs of carbon monoxide poisoning.

Paramedics and firefighters were called to a home on Sherwood Mills Boulevard in Mississauga Monday evening after several people exhibited symptoms, including vomiting.

“When we arrived there were several people out front complaining of conditions from carbon monoxide,” Mississauga Fire Captain Mike Sullivan said.

Firefighters administered oxygen to the people and assisted paramedics in treating them before they were taken to hospital.

“We checked the entire home. There was carbon monoxide through the entire home,” Sullivan said.

Mississauga Fire said the dangerous gas was detected at 200 parts per million at the home. A carbon monoxide alarm will usually sound when levels hit 45 parts per million. While the levels aren’t high enough to be fatal, they were above the acceptable limit, firefighters said.

It’s not yet clear what caused the leak, but repairs were conducted to the home’s heating system in the basement earlier in the day, Mississauga Fire said.

“There was some maintenance work being done on the house and Enbridge is investigating to see what exactly happened and what caused the carbon monoxide leak,” Sullivan said.

Peel Paramedic Services said all the patients transported are expected to be fine, but they will be checked over as a precaution.

It’s not yet clear whether the home had working carbon monoxide detectors. Firefighters took the opportunity to remind people that the devices can save lives.

“Make sure you have at least one working CO detector on the top floor of your home,” Sullivan said.

“We prefer to see one on every floor.  If you have people in bedrooms in the basement, definitely have one in the basement as well.”