Carbon monoxide (CO) is an invisible, odorless, tasteless gas that is produced when a carbon-based fuel burns. Since carbon-based fuels are gasoline, propane, charcoal, oil, etc., sources of CO on your pleasure craft may include gasoline engines, gas generators, cooking ranges, and heaters.
CO poisoning occurs when CO gas enters the body and the CO cuts off the oxygen supply to the body. CO can make you sick in seconds. In high enough concentrations, even a few breaths can be fatal.
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.