Leaks of lethal fumes most common in winter

Importance of CO alarms is stressed

December 12, 2010|By Jacques Kelly, The Baltimore Sun

Carbon monoxide leaks occur most often in winter, typically occurring when an improperly vented furnace is turned on for the season and worsening as the weather grows colder and the furnace runs more frequently.

The lethal, odorless fumes are also associated with improperly vented hot water heaters, as well as with generators powered by gasoline or kerosene. People can also suffer carbon monoxide poisoning while warming up a car in a closed garage.

"Carbon monoxide is silent and there is no smoke associated with it," Clifford S. Mitchell, assistant director for environmental health and food safety at the Maryland Department of Health and Mental Hygiene, said Sunday. "We stress the importance of being alert, of installing detectors and of not using stoves or ovens as a heating source."

He said that with carbon monoxide poisoning, "it does not take long to go from a state of lightheadedness or dizziness to a fatality."

Maryland law requires hardwired carbon monoxide alarms in a central location outside each sleeping area within specified dwellings constructed after Jan. 1, 2008. These include one- and two-family structures, multifamily dwellings or apartments, hotels, motels and dormitories. .

Carbon monoxide is the leading cause of accidental poisoning in the United States, killing more than 2,100 people per year, according to The Journal of the American Medical Association.

Carbon monoxide, or CO, binds with hemoglobin and reduces the amount of oxygen the blood can carry. The heart and brain, especially, become oxygen-starved when exposed to carbon monoxide. Even low levels of exposure, over long periods, appear to have significant health consequences.

Survivors can recover fully, but symptoms may linger in some cases. A recent Brigham Young University study of 100 victims of acute CO poisoning found that 25 percent suffered permanent brain injury, including slower mental processing, memory loss, nerve damage, depression, anxiety and personality changes.

The federal Occupational Safety and Health Administration permits exposure of 50 parts per million over an eight-hour shift. The Environmental Protection Agency and most local fire departments and code officials set 35 ppm as the danger threshold.

But medical studies suggest that even lower levels can cause long-term harm. In 2009, scientists at UCLA exposed a group of pregnant rats to CO levels of 25 ppm and found brain damage in the newborns. A researcher at Yale University, whose study of 9.3 million Medicare patient records was published the same year, found that the risk of hospitalization for cardiovascular disease in patients 65 or older increased proportionately with their level of carbon monoxide exposure, even at levels as low as one part per million.

Jacques.kelly@baltsun.com

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