Carbon monoxide (CO) is an invisible, odorless, tasteless gas that is produced when a carbon-based fuel burns. CO can make you sick in seconds. In high enough concentrations, even a few breaths can be fatal. Sources of CO on your boat may include gasoline engines, gas generators, cooking ranges, and heaters.
Early symptoms of CO poisoning include irritated eyes, headache, nausea, weakness, and dizziness. They often are confused with seasickness or intoxication. Move anyone with these symptoms to fresh air immediately. Seek medical attention—unless you’re sure it’s not CO.