Prevention is Better than cure.. Please read this and follow...
A friend in our group passed away last week due to carbon-monoxide poisoning. It happened when she lighted an aroma therapeutic candle for the night in a room with air-conditioner ON.
Due to lack of oxygen in the room, the burning of the candle cannot fully oxidize & thus forms dangerous carbon monoxide.
Carbon monoxide will prevent oxygen exchange in the lungs, resulting in the person dozing off to a state of unconsciousness & eventually death in less than an hour, depending on the room size.