TAMPA — Hours after their 43-foot boat left a Clearwater dock last week, three members of a nine-person fishing party decided to take a nap in the cabin while the boat headed back in.

Once the boat was moored in Clearwater, someone tried to rouse the sleeping trio. Panic set in when they would not wake up. All three survived after being hospitalized for carbon monoxide poisoning.

Initial reports from the Coast Guard indicate exhaust from the engines entered the cabin.

Carbon monoxide, or CO, is a deadly, odorless and colorless gas. It’s a byproduct of gasoline engine operation. CO enters the lungs and blocks the ability of oxygen to get to the bloodstream, according to the Coast Guard. Those inhaling the fumes gradually become sick or, in high concentrations, die.

The Coast Guard warns that fumes can accumulate around boat engines or gas-powered generators that often are used to run air conditioners. Enclosed cabins and the areas behind a boat are especially at risk.

According to information on the Mayo Clinic Web site, CO poisoning has killed at least 20 boaters since 1990 and has made as many as 400 more ill, but that could be understated.

Discovering A Danger

Phil Cappel, with the Coast Guard’s recreational boating division in Washington, said that for years carbon monoxide poisoning among boaters was misdiagnosed and underreported. Symptoms are similar to seasickness or drunkenness. Boaters who inhale CO can suffer nausea, weakness and dizziness.

Since 2000, when the Coast Guard started looking more closely at CO poisoning, officials have determined that carbon monoxide caused the deaths of many boaters, including some surfing on a platform attached to the rear of a boat — now considered a potentially deadly activity.

Initial fire department reports stated that the boat in the Clearwater incident had diesel engines. Coast Guard officials since have said the engines are gasoline.

A gas engine can give off CO levels as high as 40,000 parts per million, Cappel said. A diesel engine gives off about 500 parts per million.

Cappel, however, said not to assume you’re safe because you have a diesel engine.

Alarms Are Best

Since 2003, all new gasoline-powered boats more than 20 feet long and with cabins come with carbon monoxide alarms. At least one generator company, Westerbeke, of Taunton, Mass., has developed a gasoline generator with minimal CO output. It will be available soon. Other companies are expected to make similar developments, Cappel said.

David Buddingh, the marketing manager for MTI Industries in Volo, Ill., said CO alarms produced by his company adhere to marine standards. They can withstand excessive vibration and temperature as well as saltwater.

Similar to smoke alarms, the unit makes a loud noise when carbon monoxide levels reach dangerous levels.

If someone is affected by carbon monoxide, immediately move them to fresh air and seek medical attention, the Coast Guard says.

For information and tips on how to make your boat safe, visit and follow the link to the carbon monoxide advisory.

Your Safety appears weekly. If you have an idea or comment, call reporters Valerie Kalfrin or Thomas W. Krause at (813) 259-7800.

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