Robert Adler, acting chairman of the U.S. Consumer Product Safety Commission, said an agency report found portable generators were linked to more than 85 percent of non-fire CO deaths associated with engine-driven tools, or 800 out of 931 deaths, during a 14-year period from 1999 to 2012.
However, most of the deaths occurred since 2005, when Hurricane Katrina and a series of winter ice storms hit the United States and power was lost for days.
The study, by CPSC staff, found 23 percent of generator-related fatalities involved African Americans although they make up about 12 percent of the U.S. population.
Men of any race were most likely to die of CO poisoning from generators, accounting for 73 percent of the deaths, the study said.
Most of the generator fatalities, or 74 percent, occurred at fixed-structure homes -- often inside.
Portable generators have fuel-burning engines. Engine exhaust contains high levels of poisonous carbon monoxide, which can be fatal within minutes if used indoors, other enclosed spaces, such as garages, crawlspaces, sheds, or too close to the home, Adler said.
The CPSC urges consumers to only use generators outside, and at least 20 feet from the home, away from windows and vents, to allow proper ventilation. Generators should never be used inside the house, basement, garage, shed or crawlspace, even if there is ventilation.
Half of the generator-related deaths occurred in the four coldest months of the year, November through February, because of generator use during power outages. Electricity turned off by the power company due to a bill dispute or non-payment also was a factor in some generator-related deaths, the study found.