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How hurricanes kill -- it's not always what you think

Hurricane Sandy is already stressing millions of people living on the eastern seaboard, but it’s not likely to kill anywhere near the number of people who would have died in such a storm 100 years ago. That’s because weather and emergency officials can get people out of the worst flood zones in time.

So what are the most likely 21st century causes of death? Carbon monoxide poisoning often leads the list, as people turn to grills and gas stoves in power outages. Flash flooding and storm surges are also big killers.

Each hurricane is different and while a large percentage of deaths are from drowning, it’s not necessarily always the main cause. Heart attacks can also kill people, especially the elderly.

Katrina, which hit the Gulf Coast in 2005, was the deadliest hurricane this century. Officials tried to evacuate residents in low-lying areas, but several hundred people died in Louisiana when levees failed and floodwaters poured in, quickly and silently, as people slept.

Louisiana’s chief health official, Dr. Raoult Ratard, and colleagues counted 971 deaths in Louisiana alone that could be directly blamed on Katrina. Forty percent had drowned, 25 percent of people died from injuries including carbon monoxide poisoning and 11 percent died from heart conditions, which may have been exacerbated by stress or lack of access to medical care. Nearly, half, 49 percent, of the victims were aged 75 or older – showing how the frail are often most at risk.

Carbon monoxide poisoning – usually listed under injuries – killed 10 people in Alabama and Texas after Katrina and a second hurricane, Rita, hit and power went out, often for weeks.

“Few homes had functioning carbon monoxide detectors,” Centers for Disease Control and Prevention and state health officials wrote in a report published afterwards. “CDC continues to recommend that generators be placed far from homes, away from window air conditioners,  and that carbon monoxide detectors be used by all households operating gasoline-powered appliances (e.g., generators and gas furnaces), with batteries replaced yearly.”

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Carbon monoxide is an odorless gas generated when natural gas, gasoline, coal and other fuels are burned. Victims usually don’t notice they are being affected and they can die in their sleep. The first symptom is often sleepiness or nausea, as well as headache.

It can be a problem any time of year but especially during power outages as people turn to other sources to cook and to heat or cool their homes. “Don't run a car or truck inside a garage attached to your house, even if you leave the door open. Don't heat your house with a gas oven,” CDC cautions.

In 2008, Hurricane Ike hit the Texas coast near Galveston, killing 74 people in Texas and Louisiana. The largest percentage were people who died from carbon monoxide poisoning after the storm had passed and left 2.3 million people without power – 13 people died this way, state health offiicials reported. Eight people drowned and 12 died of heart attacks, strokes and other heart-related causes.

Anthony Arguez and James Elsner of Florida State University analyzed hurricane deaths and found that, even though more people live along the coasts, they are far less likely to die in hurricanes than in the days before highways and warning systems made it easy to escape the most dangerous areas.

In the past 100 years or so, they found, hurricanes have killed about 15,000 people – about half of them in 1900 when Galveston, Texas was destroyed by a hurricane. The storm surge – created when winds blow seawater up onto coastal areas -- was the biggest killer. Storm surges have been among Sandy's first effects on New York, New Jersey and Delaware.

“At least 1,500 persons lost their lives during Katrina and many of those deaths occurred directly, or indirectly, as a result of storm surge,” the National Hurricane Center says on its website.

Flash floods can also be a risk – not so much to people in homes, but to those out and about on foot and in cars. Even six inches of fast-moving water and pull a person down if they’re wading in it, and cars can be pulled into rivers or streams.

Live blog: Updates on Hurricane Sandy

When Hurricane Floyd hit North Carolina in 1999, dropping 20 inches of rain, most of those who died drowned when they were trapped in cars trying to navigate floodwaters, state health officials reported. Of the 52 people who died during and directly after Floyd, 24 died in cars, and seven, including five rescue workers, died trying to escape floodwaters by boat.

While people may worry about infectious diseases after hurricanes cause floods, they haven't historically been a major cause of death or illness. Health officials also issue detailed warnings about food poisoning -- a danger when power outages knock out refrigerators. But statistics don't indicate many deaths from foodborne illness after U.S. hurricanes.

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