No, you cannot smell carbon monoxide. It is a colorless, odorless, tasteless, and nonirritating gas, which makes it very dangerous because you cannot detect its presence without a carbon monoxide detector. This gas is produced by the incomplete burning of fuel and can build up to dangerous levels without any sensory warning. Because it cannot be smelled, carbon monoxide poisoning is often called the "silent killer," and the best protection against it is having working carbon monoxide detectors installed in your home or environment to alert you to its presence.