Each year there are dozens of deaths related to carbon monoxide poisoning from boats. Carbon monoxide is a deadly gas that is odorless, colorless and tasteless. It is found in the exhaust emitted from the electric generator and drive engine. The risk of danger affects a variety of boating enthusiasts.

Federal officials have known for some time that carbon monoxide can reach lethal concentrations from generator exhaust that gathers at the stern of houseboats, but only in the last few years have they found evidence that carbon monoxide can gather in deadly concentrations behind ski boats, cabin cruisers and even personal watercraft. The highest concentrations of CO are often around swim decks, an area where occupants frequently sit while a boat idles or is traveling at low-speed and where the exhaust ports are located.

Some tests show as much as 30,000 ppm. How bad is that? As little as 200 ppm of CO can be deadly. High levels of carbon monoxide can be fatal causing death within minutes. It is suspected that carbon monoxide poisoning related to boating is underreported because the death may appear as a drowning.

The risk of high carbon monoxide poisoning may be reduced through proper boat design. For example, many houseboats may be retrofitted with a vertical exhaust system that routes the exhaust away from occupants. National Institute for Occupational Safety and Health (NIOSH) has evaluated the “dry stack” exhaust system and found that the stack exhaust system is extremely effective at removing CO from the occupant environment. The data showed that the vertical stack exhaust was a simple and effective control that performed well during all the evaluations.

Boaters should be cautious when participating in any activity at the rear of the boat where emissions are usually heaviest.

Symptoms of Carbon Monoxide Poisoning. 

Low levels of carbon monoxide poisoning can be confused with flu symptoms or food poisoning. Some of the symptoms are:

  • Shortness of breath
  • Mild nausea
  • Mild headaches

Moderate levels of carbon monoxide exposure can cause death if the following symptoms persist.

  • Headaches
  • Dizziness
  • Nausea
  • Light-headedness

So, while out on the lake this summer, keep these symptoms in mind. If these symptoms occur while boating, immediate treatment should be sought.