As CO levels increase and remain above 70 ppm, symptoms become more noticeable and can include headache, fatigue and nausea. At sustained CO concentrations above 150 to 200 ppm, disorientation, unconsciousness, and death are possible.

How much carbon monoxide does it take to poison you?

For instance, a concentration of 400 ppm will cause headaches in 1 to 2 hours. In 3 to 5 hours the same concentration can lead to unconsciousness and death.

Is CO considered toxic?

Carbon monoxide (CO) is a poisonous, colorless, odorless and tasteless gas. Although it has no detectable odor, CO is often mixed with other gases that do have an odor. So, you can inhale carbon monoxide right along with gases that you can smell and not even know that CO is present.