Carbon Monoxide

Carbon monoxide (CO) is an odorless, colorless, tasteless gas produced by the burning of various fuels, especially natural gas, coal/charcoal, wood stoves/fireplaces, tobacco, oil, kerosene and propane.
CO poisonings can occur from car exhaust or faulty furnace fumes filling up a small space- they also often occur during power outages related to severe storms due to the increased use of generators.