What is Carbon Monoxide (CO)?
Carbon monoxide is a potentially deadly gas produced any time a carbon-based fuel, such as gasoline, propane, charcoal, or oil, burns. Sources on a boat include gasoline engines, generators, cooking ranges, and space and water heaters. Cold or poorly-tuned engines produce more carbon monoxide than warm, properly-tuned engines. Carbon monoxide is colorless, odorless, and tasteless, and mixes evenly with the air.
What is a CO incident as it applies to boating?
Boaters have been injured or killed by exposure to carbon monoxide. Most incidents occur on older boats and within the cabin or other enclosed areas. Exhaust leaks, the leading cause of death by carbon monoxide, can allow carbon monoxide to migrate throughout the boat and into enclosed areas. New areas of concern are the rear deck near the swim platform with the generator or engines running; teak surfing or dragging behind a slow-moving boat; and a backdraft effect on many vessel types. Regular maintenance and proper boat operation can reduce the risk of injury from carbon monoxide.
For more information, see the Carbon Monoxide flyer produced by the National Safe Boating Council
What does CO do to the human body?
Carbon monoxide is absorbed by the lungs and reacts with blood hemoglobin to form carboxyhemoglobin, which reduces the oxygen-carrying capacity of the blood. The result is a lack of oxygen for the tissues with the subsequent tissue death and, if exposure is prolonged, death of the individual. Altitude, age, alcohol consumption, and certain health problems will increase the effects of carbon monoxide on an individual. Physical exertion accelerates the rate at which the blood absorbs carbon monoxide.
Human symptoms of a CO incident:
| Watery/itchy eyes |
Loss of physical coordination |
Nausea |
| Flushed appearance |
Ringing in the ears |
Dizziness |
| Throbbing temples |
Tightness across the chest |
Fatigue |
| Inattentiveness |
Headache |
Vomiting |
| Inability to think coherently |
Incoherence |
Collapse |
| Slurred speech |
Red or pink skin |
Convulsions |
Symptoms may appear as intoxication, seasickness, or heat exhaustion.
Are recreational boating incidents involving CO exposure reportable to the U.S. Coast Guard?
An incident report to the Coast Guard is required for deaths or injuries resulting from carbon monoxide generated from auxiliary vessel equipment (including but not limited to stoves, heaters, refrigerators, generators, and hot water heaters), another vessel's exhaust, or the exhaust of the vessel on which persons were either aboard or in close proximity (CG-BSX Policy Letter 23-01, CH-1 (26 Sep 2023) - Recreational Boating Incident Reporting).
Applicable standard for CO incident prevention
- ABYC Standard A-24: Installation of Carbon Monoxide Detectors and Alarms (July 2020)
With appreciation to The American Boat & Yacht Council (ABYC) and the National Safe Boating Council for supplying source material for this summary.