When you inhale CO, it bonds with hemoglobin in your blood and displaces the oxygen. This process can eventually displace enough oxygen to cause serious injury or death. With mild exposure you might feel flu-like symptoms, like slight headaches, nausea, vomiting and fatigue. With moderate exposure you might experience a throbbing headache, drowsiness, confusion, and a fast heart rate.
Extreme exposure can cause convulsions, unconsciousness, or heart and lung failure.
Prolonged exposure can cause brain damage or death. Everyone is at risk for carbon monoxide poisoning. One reason is that carbon monoxide has no smell, no color and no taste. You can' t tell its there unless you have a carbon monoxide alarm, or unless you start feeling symptoms of CO poisoning. Carbon monoxide is a natural by-product of incomplete combustion.