As temperatures drop, the danger of carbon monoxide poisoning begins to rise. Nearly half of all accidental carbon monoxide deaths occur in January, February and March. Carbon monoxide is a colorless, odorless gas that can be released from poorly working or unvented furnaces or gasoline-powered tools and equipment. Church Mutual Insurance Company recommends having all furnaces, gas stoves and fireplaces checked annually by a qualified professional to verify they are working properly and have adequate ventilation. There are a number of signs that could indicate a CO problem. Read more.