Fad Turns Fatal

Boat/US Magazine, Nov, 2001 by Elaine Dickinson

Despite extensive warnings and media coverage throughout the year, carbon monoxide in exhaust from boat engines found new ways to take lives this summer. In August, the U.S. Coast Guard issued another warning about the deadly gas, this time about a new fad called "teak surfing" from swim platforms.

At least seven have died, most of them young people, from carbon monoxide poisoning after "surfing" behind a moving vessel by hanging onto the swim platform as the boat picks up speed and then letting go to body surf the wake.

While the most obvious hazard would seem to be the proximity to the boat's propellers, the hidden danger is the extremely high concentration of carbon monoxide (CO) at the stern of the boat.

"The obvious thrill it offers is what makes it enticing," said Capt. Scott Evans, chief of the Coast Guard's Office of Boating Safety. "But it kills ... It puts the individual directly in the path of the vessel's exhaust where they breathe in dangerous levels of carbon monoxide. And it doesn't stop there. In order to 'teak/drag surf' you cannot wear a life jacket, the two don't mix, and this is a recipe for tragedy."

The first Coast Guard warning was issued in July, after an 18-year-old boy died behind a ski boat on Lake Powell, a federal lake between Arizona and Utah. The boy died within five minutes of breathing the boat's exhaust and an autopsy revealed a CO concentration in his blood of 56% (a normal level is less than 1%).

Testing of CO levels conducted by the National Institute of Occupational Safety and Health (NIOSH), a federal agency that got involved in researching a string of CO deaths on houseboats last year, found concentrations of the gas as high as 26,700 parts per million in the outdoors air space above the swim platform of the ski boat involved in this fatality; 1,200 parts per million are considered dangerous.

Officials know of at least seven deaths of young people over the past six years, two on Lake Powell, and others in California, Alabama, Tennessee, Ohio and, in August, a 14-year-old boy in Connecticut. He was being towed behind a personal watercraft. Evans said he suspects there may be more fatalities but they were reported as drownings, not CO poisonings.

Boat operators are being warned to not allow anyone to swim near or sit on the swim platform while the engine, or a gas generator, is running. The death of a girl, age 16, from Syracuse, NY, occurred while she was swimming behind the boat and the engine was just idling.

Researchers say it's difficult to measure exactly how deadly fumes may collect and linger behind a boat, putting swimmers, and even tubers and waterskiers in danger. The symptoms of CO poisoning can come on slowly over hours of exposure and may appear to be other maladies. Symptoms include headaches, nausea, lightheadedness, dizziness and fatigue.

Carbon monoxide made headlines this year after NIOSH collected data on a string of houseboat deaths at Lake Powell that revealed a "death zone" beneath certain houseboats where just a few breaths by a swimmer were lethal enough to cause almost instant unconsciousness and death. The zone is an air cavity beneath the swim platform where gas generator exhaust ports are located.

The deaths of two young brothers in September 2000 in this air cavity led to a nationwide recall of all houseboats with this design in February, as well as a congressional hearing in May in which the boys' parents, Ken and Bambi Dixey of Colorado, begged committee members to prevent any more of these types of accidents.

According to the Coast Guard office handling the recall, some 1,080 houseboats were subject to the recall - requiring a retrofit of the generator exhaust ports at the manufacturer's expense if the boat is five years old or less - and nearly 800 had been fixed by September. BoatU.S. testified in May that the recall period for all boats should be extended to 10 years, the same as it is for cars. Some 1,650 houseboats subject to the recall were over the five-year limit and not required to be fixed under current rules, although some manufacturers have done so. In the past decade, NIOSH reported there have been at least 44 CO deaths and 265 poisonings at the stern of all kinds of boats.

NIOSH recently issued a new report on three types of remedies for the carbon monoxide hazard on houseboats. They conducted testing over several days at Lake Powell using emission control devices, an exhaust stack extending nine feet above the upper deck of the boat and a device that prevents the generator from running while the swim platform or swim ladder is unlocked.

Dr. Jane McCammon of NIOSH, who has been conducting the CO research, said most effective was the emission control device, similar to a catalytic converter on a car which more completely burns up gas exhaust. Also effective was a tall stack exhaust port which expels the fumes above the boat where they can more quickly dissipate in the air. One big drawback: the prototype emission control device they tested cost thousands of dollars. Continuing public education on the CO danger is also atop the list of remedies.