With winter on the way, state officials are reminding folks to protect themselves from carbon monoxide poisoning. It’s the leading cause of accidental poisoning in the U-S, and almost half of all carbon monoxide deaths occur during the winter. C-O is an odorless gas that’s emitted from older and unvented furnaces, and other gas-powered appliances. People have been known to die in their sleep from carbon monoxide poisoning. Two years ago, Wisconsin passed a law requiring every house to have carbon monoxide detectors – one on every floor, including the basement. Officials say people should test their C-O detectors on a regular basis, change the batteries each year, and make sure all heating appliances have proper vents.