A little less spooky, a lot safer: protect your home from CO

Once the pumpkins retire, give safety the spotlight. November 1 to 7 is Carbon Monoxide Awareness Week and Mississauga Fire and Emergency Services (MFES) is reminding residents to check their protection about a danger that stays out of site.

Unlike Halloween’s make-believe scares, carbon monoxide (CO) poses a real risk. In 2025, MFES responded to 495 calls where CO was present in the home, up from 450 the year before. Knowing the risks, having working alarms and acting quickly can help keep you and your household safe.

Why is carbon monoxide dangerous?

Known as the “silent killer,” CO is a harmful gas people can’t see, taste or smell. It is a poisonous gas produced when fuels such as natural gas, propane, gasoline, oil, and wood do not burn completely. Sources include fuel-burning appliances, fireplaces and vehicles running in attached garages. People and pets can be affected.

You cannot see, smell or taste CO, so dangerous levels can build up unnoticed. Exposure can cause serious illness or death, and symptoms can be easy to mistake for something else. Working CO alarms provide an early warning so you can get outside and call for help.

In Ontario, CO continues to cause deaths and hospitalizations each year and remains one of the leading causes of accidental poisoning deaths in North America. CO poisoning is preventable when residents take simple steps to protect themselves and their families.

Why install carbon monoxide alarms?

CO alarms aren’t just recommended; they’re required by law. As of January 1, 2026, amendments to the Ontario Fire Code require CO alarms on every floor of homes with fuel-burning appliances, fireplaces or attached garages. The requirements also apply to many apartment and condominium units.

Beyond meeting legal requirements, CO alarms provide an early warning when dangerous levels of the gas are present, giving residents time to leave the home and seek help. Having properly installed and maintained alarms is one of the most effective ways to reduce the risk of serious injury or death from CO poisoning.

Drop-in information sessions

Interested in learning more about CO safety and prevention? Visit one of our public information sessions and speak with a MFES Public Education Officer.

Registration is not required. Community appearances during Carbon Monoxide Awareness Week include:

• Tuesday, November 3
  • 5 to 7 p.m. at Heartland Town Centre Canadian Tire (5970 Mavis Road)
• Thursday, November 5
  • 5 to 7 p.m. at Terry Fox Way Home Depot (5975 Terry Fox Way)

Stay safe, it’s the law

If you live in a condo or apartment, a CO alarm may be required in your unit if:

• Your unit contains a fuel-burning appliance or fireplace.
• Your unit is located beside, above or below a service room containing fuel-burning equipment.
• Your unit is located beside, above or below a parking garage.
• Your unit receives heated air from a fuel-burning appliance located elsewhere in the building.

Property owners and landlords are responsible for installing and maintaining required CO alarms. Residents can help by ensuring alarms are working properly and reporting issues when they arise.

Failure to comply with CO alarm requirements may result in fines and penalties.

Keep protection working year-round

Make these steps part of your household routine:

• Test carbon monoxide alarms monthly.
• Replace alarms according to the manufacturer’s instructions.
• Keep alarms free from obstructions and follow all manufacturer guidelines.
• Have fuel-burning appliances and vents inspected annually.

Symptoms of carbon monoxide poisoning

One of the dangers of CO is that exposure can be difficult to recognize. Symptoms are often mistaken for the flu, food poisoning or general tiredness because they can develop gradually and without warning.

The effects can be especially dangerous while people are sleeping, as they may not notice the symptoms or realize they are being exposed to CO.

Common symptoms may include:

• Headaches
• Dizziness
• Weakness
• Nausea or vomiting
• Confusion
• Chest pain

If multiple people in your household experience these symptoms at the same time, or symptoms improve when you leave the home and return when you come back, CO could be the cause.

If you suspect carbon monoxide exposure, get everyone outside immediately and call 911 from a safe location, even if your alarm has not sounded. Seek medical attention immediately if anyone has symptoms.

What to do if your CO alarm sounds

Never ignore a CO alarm. Unlike a smoke alarm, a CO alarm may alert you to a danger you cannot see, smell or taste. When an alarm sounds, every second counts.

If your CO alarm is triggered or you suspect CO is present in your home:

• Move everyone, including pets, to fresh air immediately.
• Call 911 from a safe location.
• Do not re-enter the home until it has been deemed safe by emergency responders.
• If anyone is experiencing symptoms of CO poisoning, seek medical attention immediately.

Halloween scares come and go, carbon monoxide safety matters all year. This November 1 to 7, make time to test your alarms, review the warning signs and ensure everyone at home knows what to do if an alarm sounds. Responding right away can save lives.

Learn more about and alarm requirements at mississauga.ca/fire.

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• Emergency and Preparedness
• Fire and Emergency Services
• Public Safety