Unlike CO₂, carbon monoxide (CO) is a silent, deadly gas. It’s colorless, odorless, and tasteless—and it can be lethal in high doses.

Common indoor sources:

• Gas stoves and ovens
• Fireplaces
• Water heaters
• Furnaces
• Vehicles running in attached garages
• Portable generators or gas-powered tools used indoors or too close to the house

Why it’s dangerous: CO binds to hemoglobin in your blood, blocking oxygen from being carried throughout your body.

Symptoms of CO poisoning include:

• Headaches
• Dizziness
• Confusion
• Nausea or vomiting
• Loss of consciousness
• Death (at high levels or with long exposure)