(Bismarck, ND) — A reminder to get your furnace checked as winter sets in. North Dakota is in the top five states for carbon monoxide poisoning accidents. The clear, odorless gas can be deadly. Most poisonings happen at the beginning of winter when people are firing up their furnaces and warming up their cars in garages. Now is the perfect time to install carbon monoxide detectors in your home and test them once a month.