If a gas lamp is severely knocked the following may happen: The glass shield surrounding the burner may crack and leave the flame exposed, creating a potential fire hazard. The mantle may break, effectively stopping the lantern from working at all. These lamps must not be used in one, two or three person tents due to the poisonous fumes they emit (carbon monoxide), as well as the fire risk from heat and from being knocked over in a confined space.