Lake Powell

Lake Powell

Safety Bulletin - Carbon Monoxide

AVOID THESE DEATH ZONES: Swimming near or under the back deck or swim platform. Carbon monoxide (CO) from exhaust pipes of inboard engines and generators build up inside and outside the boat in areas near exhaust vents. STAY AWAY from these exhaust vent areas and DO NOT swim in these areas when the motor or generator is operating. On calm days, wait at least 15 minutes after the motor or generator has been shut off before entering these areas. NEVER enter an enclosed area under a swim platform where exhaust is vented, not even for a second; it only takes one or two breaths of the air in this "death chamber" for it to be fatal.

Carbon Monoxide Death Chamber

Blockage of exhaust outlets can cause carbon monoxide to accumulate in the cabin and cockpit area - even when hatches, windows, portholes, and doors are closed.

Blockage of Exhaust Outlets

Exhaust from another vessel that is docked, beached, or anchored alongside your boat can emit poisonous carbon monoxide gas into the cabin and cockpit of your boat. Even with properly vented exhaust, your boat should be a minimum of 20 feet from the nearest boat that is running a generator or engine.

Exhaust from Another Vessel

Slow speeds or idling in the water can cause carbon monoxide gas to accumulate in the cabin, cockpit, bridge, and aft deck, even in an open area. A tailwind (foce of wind entering from aft section of the motorboat) can also increase acculmulation.

Exhaust from Another Vessel

The "station wagon effect" or backdrafting can cause carbon monoxide to accumulate inside the cabin, cockpit, and bridge when operating the boat at a high bow angle, with improper or heavy loading or if there is an opening which draws in exhaust.


This effect can also cause carbon monoxide to accumulate inside the cabin, cockpit, aft deck, and bridge when protective coverings are used and the boat is underway.

Teak surfing, dragging, and water skiing within 20 feet of a moving watercraft can be fatal. is an opening which draws in exhaust.

Teak Surfing

Carbon Monoxide Facts

  • Carbon monoxide is a potentially deadly gas produced any time a carbon-based fuel, such as gasoline, propane, charcoal, or oil, burns. Sources on your 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 testeless and mixes evenly with the air. It enters your bloodstream through the lungs and displaces the oxygen your body needs. Early symptoms of carbon monoxide poisoning: irritated eyes, headache, nausea, weakness, or intoxication. Prolonged exposure to low concentrations or very short exposure to high concentrations can lead to death.
  • Each year, boaters are injured or killed by 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 and teak surfing or dragging behind a slow moving boat. /regular maintenance and proper boat operation can reduce the risk of injury from carbon monoxide.
  • All carbon monoxide poisonings are preventable!