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.