Carbon Monoxide (CO)

What is Carbon Monoxide (CO)?

  • CO is an odorless, colorless, and tasteless deadly gas.
  • CO is made anytime fuel (oil, gas, wood) is burned.
  • CO poisoning can occur from faulty furnace operation or blocked exhaust systems.


Possible sources include:

  • Furnaces
  • Charcoal or kerosene heaters
  • Coal, wood or gas stoves
  • Propane grills (do not use inside)
  • Running cars in attached garages
  • Tobacco smoke
  • Motorboats and houseboats


  • Use a CO detector.
  • Have your heating system serviced yearly.
  • Do not use charcoal or gas grills in your home or in a tent.
  • Do not use the oven to heat your home.
  • Unplug portable heaters while sleeping.
  • If you think a faulty appliance may be letting out large amounts of CO, call your local fire department for assistance in testing the air for CO.


  • Symptoms of CO poisoning include headache, nausea and vomiting, weakness, fatigue, and confusion. Symptoms can mimic the flu.
  • If several people in the household become ill at the same time, it may not “just be the flu.”

What to Do

More Information

For more information, visit http://kingcounty.gov.

Want to print a copy of this information?  We have a Carbon Monoxide Fact Sheet available in pdf.