Phoenix The Coast Guard has issued a mandatory nationwide recall for houseboats with rear exhaust vents that have been linked to more than 100 carbon monoxide poisonings and at least seven deaths in Arizona.
Coast Guard spokesman James O'Dell said at least 500 and perhaps thousands of houseboats could be recalled.
Six manufacturers, including the country's two largest, already have agreed to voluntarily recall boats with the design flaw, which allows carbon monoxide to build up near swim platforms on the backs of the houseboats and overcome swimmers in the water and passengers on board.
"This is what I have been looking for all along," said Dr. Robert Baron, who headed a federal investigation into some deaths at Lake Powell, an Arizona lake where the problem was first discovered.
The Coast Guard began issuing recall notices Feb. 23 to manufacturers that had not responded to a Dec. 21 notification of the defect.
The poisonings at Lake Powell remained unconnected for a decade until federal officials linked the carbon monoxide to the drowning last summer of two Colorado boys there.
A subsequent investigation by the National Institute of Occupational Safety and Health and the Interior Department found seven deaths and 74 serious injuries at Lake Powell in the past decade were caused by carbon monoxide concentrated at the rear of houseboats.
Investigators found that nearly a quarter of the 3,000 houseboats on the lake contained the potentially fatal flaw: a notch below the swim platform where the generator vented odorless, colorless carbon monoxide gas.
Researchers also found evidence of such poisonings at Lake Cumberland in Kentucky and Lake Mead on the Arizona-Nevada line.