HEATING AND CARBON MONOXIDE DANGERS By Ronn Phillips, University of Missouri-Columbia If you have gas heat in your home, then one of the dangers is carbon monoxide. Carbon monoxide is tasteless, odorless and dangerous to humans, animals, and plants. Fortunately, there are many visible signs indicating the presence of carbon monoxide. Here are some signs to look for: - Black soot on or around air registers, flues, burners or access openings to appliances - Condensation of moisture on inside windows (humidifiers & vaporizers can also cause condensation) - Dead or dying houseplants and animals - Abnormal flame characteristics, such as a yellow gas flame instead of blue, flame rolling out of the front of an appliance, or flame lifting off the burner.