Last Updated: October 8, 2025
Carbon monoxide (CO) is an odorless, colorless gas that can make you sick before you even know it’s there.
Any fuel-fired appliance can be a source of carbon monoxide. Common sources inside the home include leaking furnaces or chimneys, gas or wood stoves, unvented space heaters, fireplaces, fuel-burning grills, generators, and vehicles idling in garages.
If you experience any of these symptoms, headache, dizziness, nausea, weakness, shortness of breath, flu-like symptoms (without fever), or confusion, get to fresh air immediately and seek medical attention.
Installing carbon monoxide alarms in your home can prevent exposure to CO. Avoid using unvented fuel-fired appliances indoors and have failing appliances removed or repaired by a certified professional.
For more information check out these resources:
- EPA Carbon Monoxide Fact Sheet (PDF)
- EPA Carbon Monoxide Home Infographic (PDF)
- EPA Indoor Air Quality
- VDH Carbon Monoxide