You can't see it, smell it or taste it, but carbon monoxide (CO)—a gas released when fuel is burned—can be deadly.

Wood, oil, gasoline, natural gas, kerosene and coal all produce CO. In your home, CO can come from a variety of things, such as a heating system, cooking appliance or fireplace. It's also present in fumes from vehicles, small engines and barbecues.

There's little to worry about when appliances and other devices are working right and fumes are properly vented. But when they're not, CO levels can get high enough to cause illness and death. Hundreds of people in the U.S. die every year from CO poisoning.

CO can harm anyone, but certain people are at high risk. Those especially prone to the effects of CO are infants; elderly people; and people with chronic heart disease, anemia or respiratory problems.

At low levels, CO poisoning can mimic the flu, but without a fever. Common symptoms include headache, fatigue, shortness of breath, nausea and dizziness.

At higher levels, CO poisoning can cause confusion, vomiting, a loss of consciousness and death.

If you think you might have CO poisoning, get fresh air at once. Open windows, turn off appliances or vehicles, and leave the area. Get medical attention immediately, and tell the medical staff you suspect CO poisoning.

Also, call the fire department, and don't re-enter the home until the fire department says it's safe.

According to the Centers for Disease Control and Prevention and others, there are several things you can do to protect yourself and your family from this threat:

• Each year have an expert check anything in your home that burns gas, oil or coal, such as your heating system, kitchen range and water heater.

• Install a battery-operated CO detector, and check it at least twice a year. Follow the manufacturer's advice on how and where to install it.

• Make sure all gas appliances are properly vented.

• Have your chimney checked or cleaned every year.

• Have a mechanic check your vehicle's exhaust system once a year.

• Never leave a vehicle running in the garage—even with the garage door open.

And never try to heat your home with a device not meant for the job, such as a gas range or oven, a barbecue grill, or a portable camp stove. Some people who have trouble paying their utility bills resort to using such devices for heat, but doing so can be deadly—the devices can cause CO to build up in a home.