Carbon monoxide is an odorless, invisible gas. It binds to the hemoglobin in blood, which carries oxygen throughout the body. If you have a certain amount of it in your system, even if you’re surrounded by oxygen, you will feel as though you are suffocating.
Neurologists at Baylor College of Medicine in Houston say a high level exposure to carbon monoxide can kill almost immediately. Minimal exposure causes headaches, dizziness, nausea, and sleepiness, which appear within days after exposure.
A faulty heating system is usually the source of the carbon monoxide.