By Lee Davidson
Deseret Morning News (Salt Lake City)
Copyright 2007 The Deseret News Publishing Co.
LAKE POWELL, Utah — An invisible killer stalked the waters of Lake Powell for years, causing nearly half of the "drownings" reported there. But they were not simple drownings. They were part of a mystery that saw excellent swimmers unexpectedly sink and die, sometimes after just moments in the water.
Their real killer was carbon monoxide (CO) from the exhaust of engines and houseboat generators, sometimes found in concentrations so high behind boats that lethal amounts could be inhaled literally in seconds, making victims fall unconscious and drown or die from CO poisoning itself.
Stubborn detective work identified the problem and made initially reluctant agencies act to correct boat design. But continuing work begun at Lake Powell suggests carbon monoxide still may be an unrecognized mass killer nationwide.
"There could be as many as 250 boat-related drownings per year (nationally) that are carbon monoxide poisoning first," says Jane McCammon, one of the scientists who identified the problem.
"But that is a big guess," she adds, saying other areas often do not test for carbon monoxide poisoning in blood of "drowning" victims as doctors at Lake Powell have learned to do. So she extrapolates from work at Powell and by tracking a growing list of accidental drownings nationwide that show signs of CO poisoning.
"I have no doubt that the number (of CO boating deaths) that are actually happening is much, much larger than the number that is being identified and reported," she told the Morning News.
Dr. Robert Baron, medical adviser for Glen Canyon National Recreation Area, said the saga began when medics in the early 1990s started receiving calls for people who had passed out. "By the time they arrived, they had fully regained consciousness but couldn't remember anything," he said.
Many of them had been at the rear of boats, and officials were unsure what was happening. A medic suggested it was CO poisoning. Baron questioned how that could be for boats that were stationary with no motors running. The medic said houseboats had generators for air conditioning and electricity, and they vented into water at the rear of boats.
Baron said the first confirmed case came in 1995 when a 12-year-old drowned at the rear of a houseboat, and an autopsy found high CO levels in his blood. Baron then began years of pushing the Coast Guard and National Park Service to help with more detailed investigations and to campaign for a redesign of boats.
Things changed in 2000 when two boys from Colorado -- 11-year-old Dillon Dixey and his 8-year-old brother, Logan -- went swimming under the rear swimming platform on their houseboat on Lake Powell as a generator pumped exhaust under it.
They had been there only briefly. Their mother looked through a peephole in the swim deck just as one boy sank. Despite quick rescue, the boys could not be revived.
Autopsies found lethal levels of CO in their blood. Two good swimmers dying together by an exhaust vent convinced Baron that CO was causing similar deaths. That and press attention brought McCammon in to help investigate. She is an industrial hygienist with the National Institute for Occupational Safety and Health.
When she began testing CO levels in cavities under houseboat swim platforms, she found concentrations that could be lethal after brief exposure. In 2001, the Coast Guard issued an advisory on houseboats of similar design. Recalls were issued and boats were redesigned.
But McCammon said problems were not just with houseboats. She and Baron found CO poisoning was occurring with many other types of motorboats.
Another tragedy would bring more action. After graduating high school in 2001, Chad Ethington of Centerville was "teak surfing" behind a boat. That is holding onto the rear of a slow-moving boat and riding the wake. He was overcome by CO and sank -- even though he was a water polo player who could tread water for an hour without a break.
McCammon said, "After the investigation of his death ... and related intense press coverage, we began to hear about several similar deaths" nationally. It would lead to warnings against teak surfing and bans against it in many states and by the Park Service.
But McCammon and Baron also found probable CO poisonings not just from teak surfing but among people merely riding or swimming near motor exhaust. Motorboat engines can emit the same amount of CO (caused by incomplete combustion of fuel) as up to 166 cars.
Baron and McCammon went back to re-evaluate all "drownings" at Lake Powell in recent years. They found that 48 percent of reportable boat-related "drownings" there between 1994 and 2004 "were CO poisonings first."
Extrapolating that to drownings nationwide, McCammon says CO could be causing hundreds of deaths a year.
But she said until testing for CO in blood of drowning victims becomes routine, "We will never know the true number of CO-related drownings that occur near boats. We are left to guess from data we do have."
But their work helped reduce CO deaths at Lake Powell. Chief ranger Mike Mayer said, "We haven't had a carbon-monoxide death since 2002. We've had poisonings, but people have recognized the symptoms" because of park signs, newspaper warnings and education -- and were able to take life-saving action.
Early symptoms include irritated eyes, headache, nausea and dizziness, symptoms often confused with seasickness or having too much to drink.
David Harris, boating coordinator for the Utah Division of Parks and Recreation, said his agency has been trying to spread the word with brochures and even decals for boat owners to put at stern and helm to remind passengers of CO danger. Parents and relatives of victims have also appeared at boat shows to warn others.
But he says too many still don't realize the danger.
"We had a carbon-monoxide death last year on Utah Lake. A young college student was swimming behind a boat (where the engine was running). She hadn't been swimming there long, but went under."
