Carbon monoxide is a potentially deadly gas produced by burning a carbon-based fuel, such as gasoline, propane, charcoal or oil. Carbon monoxide is colorless, odorless and tasteless, and mixes evenly in the air. It enters the bloodstream through the lungs and displaces oxygen needed by the body. Do not confuse carbon-monoxide poisoning with seasickness, intoxication or heat stress. If someone on board complains of irritated eyes, headache, nausea, weakness or dizziness, immediately move the person to fresh air and seek medical attention if necessary. Sources of carbon monoxide on boats include gasoline engines, generators, cooking ranges, and space and water heaters. Cold and poorly tuned engines produce more carbon monoxide than warm, properly tuned engines. Boat exhaust leaks are the leading cause of death by carbon monoxide. These leaks can migrate throughout the boat and into enclosed areas. Regular maintenance and proper boat operation can reduce the risk of carbon-monoxide poisoning. Other areas of concern include being on or swimming near the rear decks of houseboats with the generator or engines running. Areas on or near a boat’s swim platform are also dangerous. – Utah State Parks

It is also best to avoid teak surfing, dragging, or being towed within 20 feet of the rear of a slow-moving boat. Research indicates that high concentrations of carbon monoxide can easily be found up to 10 feet behind a slow-moving boat.