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Understanding Carbon Monoxide Poisoning and How to Prevent It

  • 4 days ago
  • 4 min read

Updated: 4 minutes ago

Metal sign saying "DANGER CARBON MONOXIDE" attached to dark gray vinyl shingles presumably on the outside of a home

Most homeowners have heard the warnings about unintentional carbon monoxide (CO) poisoning. Yet, the Centers for Disease Control and Prevention estimates that this “silent killer” causes over 100,000 emergency room visits, 14,000 hospitalizations, and 400 deaths each year in the United States. 


Since most of these incidents occur at home, this article explains what every homeowner should know about carbon monoxide poisoning: what it is, what causes it, the warning signs, and how to prevent it.


What Is Carbon Monoxide?

Carbon monoxide (CO) is a colorless, odorless gas produced when fuel burns incompletely. Because you can’t see or smell it, CO can build up inside your home without warning.


When inhaled, carbon monoxide enters the bloodstream and binds to hemoglobin (the part of your blood that carries oxygen), forming carboxyhemoglobin and preventing oxygen from reaching vital organs. This oxygen deprivation can quickly lead to serious illness — and in severe cases, death. Even low-level exposure to carbon monoxide can result in long-term health complications, including neurological damage and cardiovascular diseases.


What Causes Carbon Monoxide in the Home?

Carbon monoxide can build up in any area of the home where fuel-burning appliances or engines are used without proper ventilation. The common factor is the incomplete combustion of fuel (gas, oil, kerosene, wood, charcoal, etc.) in a confined or poorly ventilated space.


Common Sources of Carbon Monoxide


1. Heating Systems

  • Furnaces (especially older, poorly maintained, or malfunctioning units)

  • Boilers

  • Fireplaces and wood-burning stoves

  • Portable or space heaters (kerosene or gas)


2. Household Appliances

  • Gas stoves and ovens

  • Gas dryers

  • Gas water heaters


3. Vehicles

Running a car, truck, or SUV in an enclosed space like a garage — even with the door open — is a leading cause of CO poisoning. Carbon monoxide can seep from the garage into the home.


4. Outdoor Equipment Improperly Used Indoors

  • Portable generators (especially during power outages)

  • Charcoal grills or BBQs

  • Lawn mowers or other small gas-powered engines


Never operate fuel-burning equipment inside your home (including your basement), garage, or near windows.


Health Risks & Symptoms of Carbon Monoxide Exposure

Because CO robs your body of oxygen, symptoms can escalate quickly.


Early Symptoms (Often Mistaken for the Flu)

  • Headache

  • Dizziness

  • Nausea

  • Fatigue

  • Shortness of breath


Advanced Symptoms

  • Confusion

  • Blurred vision

  • Loss of coordination

  • Chest pain

  • Vomiting

  • Loss of consciousness


Higher-Risk Individuals

  • Elderly adults

  • Children

  • Pregnant women

  • Individuals with heart or lung conditions


NOTE: If multiple people in your home become sick at the same time—especially during the heating season—carbon monoxide exposure should be suspected immediately.


What to Do If You Suspect Carbon Monoxide Poisoning

If you believe carbon monoxide may be present:


  1. Move everyone outside immediately for fresh air.

  2. Call 911 or emergency services.

  3. Do not re-enter the home until professionals have declared it safe.

  4. If someone is unconscious and not breathing, begin CPR and call emergency services immediately.


Quick action can save lives.


Preventing Carbon Monoxide Poisoning


1. Install a Quality Carbon Monoxide Detector

While installing carbon monoxide detectors is critical, not all detectors provide the same level of protection. Some may sound the alarm more quickly in the presence of high CO levels, while others may detect lower levels over a longer period. 


CAUTION: Some low-cost detectors

  • Don’t sound an alarm until CO levels are already dangerous

  • Don’t show real-time CO levels

  • Have no digital display

  • Only show a green light to indicate they’re powered


>Be sure to review the specifications, features, and limitations of your CO detector to ensure it meets your household's safety needs.


What a quality CO detector offers:

  • A real-time display of CO levels (PPM readings)

  • An alert at the first sign of rising levels

  • Dual detection for carbon monoxide AND natural gas


IMPORTANT: Carbon Monoxide Is NOT the Same as Natural Gas

Many homeowners assume one detector covers both. It doesn’t. Carbon monoxide is a byproduct of incomplete combustion, while natural gas is the fuel itself.


If there’s a fuel leak from a stove, furnace, boiler, water heater, dryer, or fireplace, a CO detector will not issue a warning. For this reason, we strongly recommend installing dual-sensor detectors.


>For full-home protection, place your CO detectors in the right locations, positioning them so you can see the displays at a glance:

  • Near the boiler, furnace, or water heater

  • In the kitchen (near but not directly above the stove)

  • In the laundry room

  • Near bedrooms

  • On the main living floor


Ensure Your CO Detectors are Working 

  • Test them monthly

  • Swap out batteries annually

  • Replace the entire unit every five to seven years


2. Schedule Annual HVAC & Appliance Inspections:


  • Furnaces

  • Boilers

  • Water heaters

  • Fireplaces

  • Gas appliances


Annual heating system inspections ensure proper combustion and safe venting. Blocked chimneys or flues, cracked heat exchangers, and poorly adjusted burners are common causes of CO buildup.


3. Practice Safe Appliance Use


Ensure you are using your appliances safely:

  • Never use ovens to heat your home.

  • Never use charcoal grills indoors.

  • Never run a generator inside your home or garage or near windows.

  • Never idle a vehicle in a closed garage.


Watch for warning signs of malfunctioning appliances:

  • Yellow flames instead of blue

  • Soot buildup

  • Unusual smells or sounds


Protect Your Home with Main Stream Mechanical

Main Stream Mechanical is here to help you keep your home heating system operating safely and efficiently. We offer the following services: 

  • Furnace and boiler inspections

  • HVAC maintenance

  • Safe combustion testing

  • Professional installation of advanced CO and dual gas detectors


Contact us to schedule an appointment. 


Heating System Installation, Service & Repair in MA & NH

We have helped homeowners in Massachusetts and New Hampshire stay warm and safe for nearly 30 years. To ensure your heating system is operating as it should, call us at (978) 834-0849 or contact us through our website.

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