shocking reminder of how insidious carbon monoxide can be comes from
none other than legendary racing car driver Al Unser Sr. The Formula
1 driver who’s won the Indianapolis 500 four times and been
around running engines his entire career was nearly killed —
not on the auto racing track, but out on his boat.
Several years ago, Unser was out on a houseboat on Lake Powell, AZ,
when a storm came up and he and his crew decided to pull up their
anchors and move the boat away from some rocks. Once the boat was
re-anchored, Unser decided to dive below the boat to unsnag another
line. As he repeatedly dove and surfaced, he came up in an air space
beneath the deck, unaware that the boat’s generator was vented
into this air space and he was gulping down deadly levels of carbon
Unser does not remember how he got himself back up on the deck, by
then semi-conscious. Rushed to a hospital, he was put on oxygen and,
most fortunately, survived the incident. He now makes a point of warning
other boaters of how dangerous this odorless, colorless, tasteless
gas can be.
Carbon monoxide has been a known hazard on boats for decades, particularly
inside cabins on boats with gasoline-powered generators. But what
galvanized education and research efforts to a more urgent level was
the discovery in 2000 that many houseboats were built with a fatal
flaw. Deaths that had formerly been attributed to drowning were in
fact carbon monoxide poisonings of adults and kids who were swimming
into an air cavity, like Unser did, filled with generator exhaust.
Two boys who died, merely feet away from their parents, because they
were playing under the deck, as well as other incidents on houseboats,
resulted in congressional hearings and a U.S. Coast Guard recall of
houseboats with this particular design in 2001.
On the heels of the houseboat recall came more testing and the discovery
that boaters were also being overcome in “fresh air” poisonings,
sitting in cockpits, on stern decks and swim platforms. Consequently,
public education efforts have been ramped up to warn boaters of this
unseen hazard, but a push on another front — technology —
could also clear up the air, literally, for boaters.
CO At Its Source
Work on new engine designs to reduce the CO hazard where it originates
are moving ahead at a fast pace, prompted in part by pending new federal
“I’m pretty confident we’re moving toward an engineering
solution,” said John McKnight about the carbon monoxide hazard.
He is director of environmental and safety compliance for the National
Marine Manufacturers Association. “Before the end of this decade
we’ll have greatly reduced the carbon monoxide problem. We just
have to prove the technical feasibility of catalytic converters in
the marine environment.”
Many boaters don’t realize that marine engines produce more
carbon monoxide than cars because boat engines do not have any after-treatment
of the exhaust. Automobiles have had catalytic converters for decades
to reduce tailpipe emissions under standards set by the Environmental
Protection Agency. Only in the last decade has the EPA begun setting
standards for marine engine emissions and the job is currently only
half finished. Outboard engines are now manufactured under new EPA
standards, phased in through 2006, and the next set of regulations
will cover gasoline sterndrive and inboard engines.
“The EPA will come out with a major engine rulemaking later
this year that will include strategies for CO reduction,” said
Meanwhile, the state of California, through its powerful Air Resources
Board, is moving toward requiring catalytic converters on marine sterndrives
and inboards, ahead of the EPA. Because the state’s air pollution
was once one of the nation’s worst, the EPA grants California
special waivers to create its own emissions rules, which tend to become
the standard for the rest of the nation since manufacturers cannot
normally create a product line for just one state.
Generally, a gasoline inboard engine will generate 10,000 ppm of carbon
monoxide; if the boat is moving most of it is dispersed into the air.
But health experts say 25-50 ppm is hazardous enough to limit exposure.
At 200 ppm a person will start to feel sick with a headache, nausea,
fatigue or dizziness (often mistaken for seasickness). At 1,200 ppm
a person is in immediate danger of dying.
If catalytic converters on cars and trucks have done such a great job
of reducing tailpipe emissions, why not on boats? A catalytic converter
works by forcing engine exhaust into a honeycomb of pinholes which restricts
the molecules and creates more heat so they oxidize. This process is
a secondary burning of exhaust which results in carbon dioxide and water.
Under an ongoing joint research program of the marine industry, engine
manufacturers, the Coast Guard, EPA and California, catalyst technology
has so far only been tested on freshwater sterndrive and inboard engines.
Tests on four powerboats from 19 to 23 feet equipped with two MerCruiser
and two Indmar sterndrives and V-drives over 480 hours of operation
produced carbon monoxide reductions up to 99% (engine running at idle).
Peak levels were 200 ppm.
A follow-on series of tests of catalytic converter-equipped engines
in saltwater was to be done this summer, however, cost issues with California
have put this plan on hold. The Coast Guard and engine manufacturers
are pushing for the test to go forward because there are major safety
concerns that haven’t been addressed.
“The bigger issue is what happens with saltwater ingestion. We
know salt will corrode and the catalysts can get blocked. It’s
like putting a cork in your exhaust system,” said McKnight. “These
are all potential concerns that need to be ruled out in saltwater testing.”
The Coast Guard is also very concerned about the safety of catalytic
converters in saltwater engines because of the risk of fire and fuel
or exhaust leaks. The agency has written to the EPA on the potential
safety hazard. However, California currently has a waiver request before
the EPA to let them require catalytic converters on marine engines by
“Our main concern is what saltwater, which is much more corrosive,
will do to the exhaust systems. You are creating more heat in a small
engine space,” said Phil Cappel, executive director of the Coast
Guard’s National Boating Safety Advisory Council and former chief
of product recalls. “We have to know if our other regulations
need to change, such as type of fuel hoses.”
Even so, Cappel shares the optimism that better engine design might
eliminate the carbon monoxide hazard significantly. “We are so
far ahead of where we were five years ago,” he said.
this issue goes to press, field testing had just wrapped up on a new
marine generator reported to run 99% free of carbon monoxide. Two
Westerbeke generators were installed on two 70-foot houseboats at
Lake Mead, NV, and run on a continuous basis, along with meters to
test its effectiveness in a real boating environment in mid-March.
A CO-free marine generator would go a long way toward eliminating
both cabin and fresh air poisonings from generator exhaust such as
those that led to the houseboat recall.
“I would say the initial results look promising,” said
Dr. Scott Earnest of National Institute for Occupational Safety and
Health (NIOSH) who participated in the Lake Mead test. “This
was the first field test and we want to do it again at the end of
the boating season to see how well they do after extended use.”
CO sensors were placed in eight locations on the houseboats, inside
and out, and Tom Sutherland, vice president of sales and marketing
for Westerbeke, said he saw the NIOSH chart after the first day of
testing that showed a cold start of the generator at 90 ppm of CO
and then it ran at zero to 6 ppm of CO for the rest of the day. “They
were pleasantly shocked to see the results,” Sutherland said
of the federal observers.
Westerbeke is now selling their Safe-CO™ gasoline generator
models in 10 sizes from 2.7 kW to 22.5 kW. Prices are expected to
be about 20% higher than standard models. The new product won the
2005 Innovations Award from NMMA, judged by writers from Boating Writers
International. Kohler is reportedly also working on a similar generator
to reduce CO.
In addition, MerCruiser and Indmar unveiled prototypes of sterndrives
with catalytic converters at fall and winter boat shows, but they
are still in the research and development phase. An engineer with
Mercury said they are moving ahead in anticipation of a 2008 EPA requirement.
“It’s impressive that this much progress has been made,”
said Earnest. “Developing engineering controls should make a
big difference in preventing poisonings in the future.”
In continuing research on all boat CO poisonings, a joint task force
of NIOSH, the National Park Service, Coast Guard and Dept. of Interior
recently updated known cases and, surprisingly more boaters have perished
in incidents on deck than inside cabins. In cases where the location
of the victim was known, 51 died in topside poisonings, compared to
31 deaths inside of boats.
1990, researchers have found 113 deaths from carbon monoxide poisoning
on boats. A total of 458 people were involved in non-fatal poisonings.
Of the non-fatal incidents, 131 of these occurred outside on deck;
270 occurred inside. The Coast Guard suspects that as many as 15%
of boating drownings could have been CO poisonings.
Currently, a CO detector is required under industry standards on any
boat with a gas engine or generator and enclosed spaces below such
as a berth, galley or head or cabins.
Another preventative measure has been warning labels and transom placards,
particularly on rental houseboats commonly used by less experienced
boaters. California has begun requiring a placard on transoms warning
about carbon monoxide and propeller strikes which may also be distributed
nationwide by boatbuilders and the Coast Guard. In addition, a handful
of states have banned “teak surfing” — where a swimmer
hangs onto the swim platform of a moving vessel, right where the engine
exhaust is at its most lethal.
For more information on carbon monoxide and ways to protect yourself
and your guests, the BoatU.S. Foundation for Boating Safety and Clean
Water has a special Web site on carbon monoxide at www.boatus.com/foundation/grants/carbon_monoxide.htm.
— By Elaine
©BOATU.S. MAGAZINE 2005