Few parents realize that carbon monoxide -- an invisible, odorless gas -- can be a serious hazard even if you're outdoors.


Invisible, Odorless, and Scary

It started out as an idyllic summer day. Becky Smith and her family were visiting friends who had a houseboat on Missouri's sprawling Lake of the Ozarks. "The water was fabulous," recalls Smith, a nurse in Overland Park, Kansas. Safe in a life vest, her 4-year-old daughter, Natalie, swam with a bunch of adults at the back of the anchored boat. Smith had been inside the air-conditioned galley preparing dinner, then came outside to put more sunscreen on Natalie. The preschooler splashed over to the ladder, stood on a rung briefly while her mom smeared lotion on her, and jumped back into the water.

A few moments later, Natalie was floating faceup, unconscious. Another adult on the deck jumped into the water and dragged her back onto the boat. By that time, she was conscious but pale, limp, and breathing irregularly. "I was desperately trying to figure out what had happened, and the most precious thing in my life was slipping away from me," says Smith. They took a frantic ski-boat ride to reach paramedics, who whisked Natalie to the closest hospital. The emergency-room doctor quickly guessed the cause of Natalie's sudden sickness: carbon monoxide (CO).

An invisible, odorless gas produced by the incomplete burning of fuels such as gas, oil, kerosene, or wood, carbon monoxide is the most pervasive poison in our environment. Victims of carbon-monoxide poisoning can essentially suffocate. Once the gas is inhaled, it quickly binds to red blood cells -- replacing the oxygen in the blood that needs to reach the rest of the body. Many parents assume that carbon monoxide is a hazard only during the winter, when heating systems malfunction, fireplaces aren't vented properly, or people let their car engines warm up in a closed garage. But experts say that it's now an increasing risk year-round.

When Natalie stood near the back of the boat, she'd inhaled fumes produced by the houseboat's generator, which powered the air-conditioning, lights, and TV onboard. At the emergency room, tests revealed that the amount of carbon monoxide in her blood was more than 20 times the normal level. Doctors immediately gave her oxygen, and then she was airlifted to the University of Missouri Hospital, in Columbia, where she was placed in a hyperbaric chamber and the toxin was slowly removed from her blood. The next day, she was well enough to go home.

Powerful Poison

Every year, more than 500 people -- including about 30 kids -- die from unintentional carbon-monoxide poisoning, according to the Centers for Disease Control and Prevention. The U.S. Coast Guard reported 140 deaths and 714 poisonings from carbon monoxide in the boating community between 1990 and 2007, and the Consumer Product Safety Commission says that 140 deaths annually are associated with products such as generators, furnaces, grills, heaters, and stoves. But these government agencies admit that their statistics are probably incomplete. When someone is rushed to the ER after a mysterious accident or near-drowning, doctors may not think to do a blood or Breathalyzer test for carbon monoxide. "Those of us who work in this field suspect that there are many more carbon monoxide-related deaths, as well as nonfatal poisonings, than the official figures show," says David G. Penney, PhD, editor of Carbon Monoxide Toxicity.

Carbon monoxide is a growing problem because it's produced by the sorts of gas-powered products that have become more popular in the last five to 10 years. "People are being exposed to emissions from increasingly affordable equipment that seems fairly harmless," says Kevin Dunn, an industrial hygienist at the National Institute for Occupational Safety and Health (NIOSH). Millions of people have bought portable generators, for example, in case of power outages. Tests by the Environmental Protection Agency, however, have shown that a portable generator can emit as much carbon monoxide as hundreds of idling cars. Lawn mowers, leaf blowers, charcoal and gas grills, power washers, chain saws, and all-terrain vehicles can also be hazardous. Even water-skiers need to be wary: An idling ski-boat motor can create extremely high levels of carbon monoxide.

G. Scott Earnest, PhD, chief of NIOSH's Engineering and Physical Hazards branch, remembers conducting a test with a five-horsepower gasoline engine, which is typically used in portable generators and other tools. "We cranked up the engine, and within minutes there were high levels of carbon monoxide. I was shocked that a potentially deadly situation could occur so quickly."

Since carbon monoxide doesn't smell and isn't visible, parents don't think much about it -- or suspect it as a possible cause when someone gets sick. The initial symptoms -- headache, dizziness, weakness, nausea, shortness of breath, confusion -- can seem like those caused by the flu or food poisoning or by warm-weather illnesses like heat exhaustion.

Babies, as well as children who have asthma or other respiratory or heart problems, are particularly vulnerable to the effects of carbon monoxide. Pregnant women also need to be very careful, because the gas can cross the placenta and can lead to low birth weight, birth defects, or even miscarriage. Although children who are diagnosed and promptly treated can recover, exposure to carbon monoxide may cause lasting neurological damage.

Protect Your Family

It's definitely important to install carbon-monoxide alarms outside bedrooms on each floor of your home and to make sure that your furnace and chimney are inspected and cleaned every year by a qualified technician. However, detecting the gas outdoors is obviously trickier. Here are some lesser-known ways to avoid exposure both indoors and out.

Focus on problematic products. Gasoline- and diesel-powered motors usually emit carbon monoxide, as can grills, hibachis, and propane stoves. Never use any of these indoors -- not even in the garage or basement. Having a fan or an open door or window won't clear the air. Be cautious with any generator. Buy a carbon-monoxide detector to use along with it, as well a 50-foot extension cord to keep the generator far from your home when it's in use. A soft breeze could blow the gas into your house through windows, doors, vents, or cracks, and you'd never know.

Always consider carbon monoxide. Your child may not tell you that she feels dizzy, weak, or confused -- the first signs of CO poisoning -- and she might simply faint. If she suddenly loses consciousness, take her outside (or out of the water) and into fresh air and seek medical attention immediately.

Boating Safety

The Coast Guard has issued a strong warning to recreational boaters about the risk of serious injury or death from carbon-monoxide poisoning. It's crucial to take these precautions.

Turn generators off if anyone is swimming off the boat. Fatal levels of carbon monoxide can accumulate in the area between a swim platform and rear exhaust port. This is especially true for houseboats but may occur on any boat with a generator. It's safest for children to swim at the front or side of the boat.

Make sure that there is fresh air circulating throughout the boat at all times. Use exhaust blowers whenever a generator is on, and be wary of inadequately ventilated canvas enclosures on motorboats. Every boat should have a carbon-monoxide monitor on board.

Be careful when going slowly. When you're idling or cruising at a slow speed, carbon monoxide from the motor might not blow away, and it can stay at a dangerous level even after you turn off the engine. Your child can also get carbon-monoxide poisoning from the exhaust of another boat if it's next to yours. If he has symptoms of seasickness, assume that it could be carbon-monoxide poisoning and get him into fresh air fast.

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