It's a silent killer that could enter your home and you wouldn't even know it.
Carbon monoxide can invade almost any enclosed space -- from a single family home, to a hunter's tent in the woods.
When outside temperatures plummet, people in Wisconsin crank up their thermostats. But with warmth comes the risk of carbon monoxide poisoning. Symptoms resemble a head cold or the flu.
If you get home and you're feeling sick, but when you leave you feel better, or if everyone in the home gets sick at the same time, it's a good indication there may be carbon monoxide, said Eric Dahl with the Madison Fire Department.
Firefighters and EMS workers use detectors when responding to home emergency calls. They say a carbon monoxide detector, available at local hardware stores, provides early warning that can save lives.
They recommed at least one in the sleeping area. And one in each level of the home, Dahl said.
A colorless, odorless, tasteless gas, carbon monoxide invades homes when furnaces, fireplaces, stoves and water heaters are not properly maintained or ventilated. The danger is not limited to homes.
Said Dahl, It could be a space heater that runs off of propane or kerosene. It may be a generator that people are using when they're camping or hunting. If it burns fuel, it's producing carbon monoxide.
Outdoorsmen can buy a portable carbon monoxide detector that runs on batteries.
Whether it's in the house or used for travel, manufacturers recommend getting a new carbon monoxide detector every five years.
If you leave your car running for a long time in an attached garage, you face the risk of poisoning. Even if the garage door is open, fumes can still enter the house.