Carbon Monoxide

CO is a chemical asphyxiant that binds to the hemoglobin in your blood and will not allow oxygen uptake. As mentioned some symptoms of include headache, dizziness, fatigue, confusion etc. It has a 3-4 hour half-life in your blood stream, so symptoms may persist for quite some time after exposure. Nothing to fool around with and if you think you have been heavily dosed get to open air and ventilate your space and get you blood oxygen checked at the doc or ER. A CO monitor in your garage and house is always a very good idea.