What to do if a carbon monoxide alarm goes off?

Author: Anita McCullough  |  Last update: Sunday, June 1, 2025

If the alarm sounds, vacate the house. Then, it's best to call 911 or the fire department to come out and test for the source of carbon monoxide. Once they've identified what is causing carbon monoxide to be released in your home, you'll need to contact a licensed professional to service the offending appliance.

Should I worry if my carbon monoxide alarm goes off?

Yes, if a carbon monoxide (CO) alarm goes off, you should take it seriously. Here are the steps you should follow: Evacuate Immediately: Get everyone out of the building and into fresh air. Call 911: Once you are safe, call emergency services to report the alarm. They can send professionals to assess the situation.

Do carbon monoxide detectors give false alarms?

While CO detectors are designed to be reliable, various factors can cause them to beep erroneously. False alarms can be caused by incorrect installation, placement near a source of fumes or steam, or even a buildup of dust and dirt on the sensor.

What to do if carbon monoxide alarm goes off and then stops but?

Call 911 immediately and report that the alarm has gone off. Do not assume it is safe to reenter the home when the alarm stops. When you open windows and doors, it helps diminish the amount of carbon monoxide in the air, but the source may still be producing the gas.

How long should you wait after a carbon monoxide alarm goes off?

If your CO alarm is going off, you should immediately grab your family and pets and get into fresh air. Open any windows you can on your way out. Once outside, call 911. According to the CDC, the most common symptoms include headache, weakness, nausea, chest pain, confusion or vomiting [2].

What Do I Do if My Carbon Monoxide Alarm Goes Off?

What if carbon monoxide alarm goes off but no fire?

Your carbon monoxide alarm is going off for one of the following reasons: It is doing its job properly and detects CO pollution in the air. It is a false alarm caused by other household items. The detector is malfunctioning or the batteries need changing.

Will opening a window help with carbon monoxide?

If you experience symptoms that you think could be from CO poisoning: DO GET FRESH AIR IMMEDIATELY. Open doors and windows, turn off combustion appliances and leave the house.

What are two warning signs of carbon monoxide poisoning?

The most common symptoms of CO poisoning are headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion. CO symptoms are often described as “flu-like.” If you breathe in a lot of CO, it can make you pass out or kill you.

Does the fire department charge to check for carbon monoxide?

In most areas, the fire department does not charge to respond to carbon monoxide alarms or to check for the presence of CO in a residence. However, policies can vary depending on the jurisdiction or specific fire department. It's always a good idea to contact your local fire department for specifics on their policies.

Who do I call if my CO2 alarm goes off?

If your detectors go off, call 911 and evacuate the home. Be sure to notify them if anyone in the house is experiencing flu-like symptoms. The Fire Department has specialized equipment to detect and measure amounts of CO in your home.

How do I shut off the carbon monoxide alarm?

First, look for a button called 'silence' or 'reset'. Hold this button down for 10 or more seconds. Release the button, and the LED lights should blink or turn back on. Your unit might also let out a singular beep.

Can anything else trigger a carbon monoxide detector?

Even with the doors and windows open, any of these activities can trigger carbon monoxide detectors. Using a grill inside the garage or near open doors and windows–Not only is barbecuing among the most common CO-producing activities, but it can also be a fire hazard when done too close to your home.

What will my alarm do if it detects carbon monoxide?

When the carbon monoxide alarm senses a dangerous level of CO gas, the unit will emit a loud alarm pattern. The alarm pattern is four short beeps – followed by five seconds of silence – followed by four short beeps.

How to tell if carbon monoxide is in the air?

The best way to alert you and your family to unsafe levels of CO is to install a carbon monoxide detector. It works like a smoke alarm, sampling the air in your home and creating a loud alarm when levels of the gas are detected. It's important to evacuate your home immediately when your CO alarm sounds.

Will a carbon monoxide alarm go off again if you silence it?

If you “shut it off” it will not be working, so will not detect carbon monoxide. If you reset it, it will activate again if carbon monoxide is detected, as long as the battery/power supply is within normal operating limits. A low battery may cause the alarm to “fail safe” and activate to notify that it needs replacing.

How to clear carbon monoxide from a house?

If no one is feeling symptoms, ventilate the home with fresh air and turn off all potential sources of CO. That includes your oil or gas furnace, gas water heater, gas range and oven, gas dryer, gas or kerosene space heater, and any vehicle or small engine.

Should I call 911 if my carbon monoxide alarm goes off?

My carbon monoxide alarm is sounding. What should I do? Call 911 and report what is happening. Immediately leave your residence and wait for the fire department to arrive.

What to do if you detect carbon monoxide in your home?

If you notice this, call 911. Have the fire department check for CO in your house. If CO is present, the source must be repaired before it is safe to return home.

Is a carbon monoxide alarm an emergency?

If it still sounds, call the fire department. If the CO alarm sounds, immediately move to a fresh air location outdoors or by an open window or door. Make sure everyone inside the home is accounted for. Call for help from a fresh air location and stay there until emergency personnel.

What to do if a carbon monoxide alarm goes off and then stops?

If you have a carbon monoxide detector chirping and then it stops, it's important to take the situation seriously, even if the alarm is no longer sounding. Even if the alarm has stopped, get everyone out of the home to a place with fresh air.

Who can test my home for carbon monoxide?

Some municipal fire departments and utility companies will come to your home and check for carbon monoxide for free or at reduced rates. The main tool used in these tests is an electronic portable toxic multi-gas monitor.

How long does it take to get carbon monoxide out of your system?

The carbon monoxide in your body leaves through your lungs when you breathe out (exhale), but there is a delay in eliminating carbon monoxide. It takes about a full day for carbon monoxide to leave your body. 1.5 HOW CAN CARBON MONOXIDE AFFECT MY HEALTH?

What puts off carbon monoxide in a house?

The most common causes of carbon monoxide building up are incorrectly installed or poorly maintained or ventilated appliances – like stoves and hot water heaters. Poorly ventilated fireplaces and other gas- or wood-burning appliances can also pose danger.

How to test a carbon monoxide alarm?

How to test your carbon monoxide detectors to ensure they are working properly? To test your carbon monoxide detectors, press and hold the test button on the alarm. The detector will sound 4 beeps, a pause, then 4 beeps for 5-6 seconds. Refer to the user manual for your specific model.

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