Study backs lake "death zone" theory
By Judd Slivka
The Arizona Republic
December 21, 2000

A second federal study in less than a month has found that carbon monoxide fumes from houseboat generators can create a "death zone" behind the vessels.

An investigation of houseboats at Lake Cumberland, Ky., the nation's most popular houseboating destination, has found that odorless, colorless carbon monoxide gas concentrates beneath and around the swim decks of houseboats whose generators vent to the rear and beneath the platform.

The Arizona Republic reported in November that federal researchers had associated nine deaths and 102 serious injuries with carbon monoxide poisoning over the past decade at Lake Powell.

Lake Cumberland has had 44 drownings in the past decade, none obviously associated with carbon monoxide. But that, officials say, may be misleading because drowning victims are rarely tested for carbon monoxide.

"Is there a rational reason why there are deaths at Lake Powell from this and not at Lake Cumberland? I don't think so," said Jane McCammon, the head of the federal study. "It would only make sense that if this is happening at Lake Powell, this is happening elsewhere."

The Lake Cumberland study was the second investigation by the National Institute for Occupational Safety and Health since the drowning deaths of two Colorado boys this summer at Lake Powell.

The first investigation of houseboat carbon monoxide fumes was at Lake Powell. That probe found carbon monoxide concentrations as high as 30,000 parts per million, well above the 1,200 ppm exposure considered "immediately" dangerous by the federal government.

Although the Lake Cumberland numbers didn't consistently equal the extreme findings at Lake Powell, they still are well above the threshold for safety.

Researchers have focused on carbon monoxide accumulations in the area underneath a houseboat's swim deck because it looks like a cave or secret compartment, and invites children to explore it. But when a houseboat's generator, used to power the luxuries of home that modern houseboats feature, vents its exhaust below the swim deck, it can turn the cave into a lethal place, where only a few breaths can kill a person.

For example, a carbon monoxide detector placed on the swim platform of a 2000 model Stardust Cruiser while the generator was in operation recorded a reading of 4,662 ppm.

Other monitors on the boat had to be removed from the boat after topping out at more than 1,000 ppm.

A test on a 1988 Jamestown Deluxe model houseboat yielded similar results: an air sampling from the bottom of the stairs that lead down to the water from the back deck yielded a reading of 1,157 ppm.

One boat tested at Lake Powell registered 7,000 ppm of carbon monoxide over the afterdeck of the boat; a similar boat at Lake Cumberland had readings of 10,000 ppm.

Federal and state officials are now discussing doing an investigation of the drownings at Lake Cumberland. Such a study could be critical to Kentucky's economy. The nation's houseboat industry is centered in Kentucky, with 20 of the nation's 85 houseboat-registered manufacturers based in the state.

Some manufacturers have long been building boats with generators that vent to the side, rather than the back. But some companies, including industry leader Stardust, whose boats have accounted for seven of the nine carbon monoxide fatalities on Lake Powell, continue to build boats with rear-venting generators.

"We're going to start looking at clinical data, looking at death certificates and EMS run sheets," said Dr. Rice Leach, Kentucky's public health commissioner. "It is prudent to confirm your hypothesis. That's why you do a study like this, to find out if Kentucky has the same problem."

In the meantime, Coast Guard officials are awaiting final approval of a letter the service will send out to the nation's houseboat manufacturers asking for fixes for the problem.


    Copyright 2000, The Arizona Republic. All rights reserved. This article graciously provided courtesy of The Arizona Republic.