Carbon Monoxide: A Silent Killer

Carbon monoxide, sometimes called a “silent killer,” is a hazard of which all boaters and water sports participants should be aware. Because carbon monoxide (CO) is an odorless, colorless, and tasteless gas, it may affect an individual with little or no warning. CO is produced when carbon-based fuels such as gasoline or propane are burned. It is found in the exhaust of the gasoline engine on your boat.

Carbon monoxide can easily accumulate inside or outside your boat whether you’re underway, moored, or anchored. It can build up in enclosures in and around your boat. Dangerous levels of carbon monoxide can also collect at slow speeds, while idling or stopped, and even if the engine on your boat is no longer running. Keep in mind that exhaust emissions don’t just come from your engine, but the exhaust of other boats moored or floating near you can be a source of carbon monoxide.

The signs of carbon monoxide poisoning are easily overlooked because they often resemble other ailments such as seasickness or intoxication. Initial symptoms can include irritated eyes, lack of concentration, inability to think coherently, ringing in the ears, headache, dizziness, drowsiness, fatigue or nausea. More advanced symptoms are vomiting, loss of consciousness, collapse or convulsions. If the exposure level is high, loss of consciousness can occur without other symptoms showing. Death may occur if high exposure continues. The rate at which an individual absorbs CO into their body depends on many factors: age, general health, physical activity, altitude, among others. If you suspect that someone is suffering from carbon monoxide poisoning, move them to fresh air immediately and seek medical help. If the person is not breathing, perform rescue breathing or CPR, as needed, until medical help arrives.

Boaters need to be especially aware of CO poisoning risks when participating in towed water sports. Testing indicates that CO concentrations are greater in a zone at or near water level, in close proximity to the transom of a boat where exhaust outlets are located and that CO

concentrations diminish as you move up and away from that zone. We strongly recommend that you not allow any activity behind a boat that places a person in this zone. Never allow anyone to occupy the swim platform while the engine is running! Towed tubers, who tend to be young children and generally close to water level, should be towed on a long line.

Two extremely dangerous activities are “platform dragging”, also referred to as “teak surfing,” and “body surfing.” “Platform dragging” involves hanging onto the swim platform of the boat while it is in motion. “Body surfing” is lying prone on the water surface in close proximity to the transom or swim platform of a boat while the wake propels you along. Both are extremely dangerous activities and are banned in many areas. They should not be permitted on your boat or anyone else's boat! Individuals who “platform drag" or "body surf” are directly exposed to high concentrations of carbon monoxide fumes in the engine’s exhaust. In addition, these people are very close to the spinning propeller underneath the boat, which can kill or seriously injure them if they slip or get pulled beneath the swim platform.

Please pay close attention to the carbon monoxide hazard associated with motor boating. Keep you and your passengers’ safety in mind at all time. Make sure everyone riding in your boat or towed behind it is wearing proper PFD’s at all times, especially children. Also, know that operating a boat while under the influence of alcohol or drugs is extremely unsafe and against the law. Remember, boating safety and enjoyment go hand in hand – you can’t have one without the other.

For more information, visit web sites listed on this page and other pages in our Boating Safety section.