Not only charcol, anything that keeps burning in a closed room consumes the complete O2 in the room and gives out CO2 and still the burning procedure will continue resulting in the emission of CO (carbon monoxide) which is dangerous to human health coz while inhaling it the human blood cells (RBC - red blood cell containing haemoeglobin) absorb CO faster than O2 which is toxic to the body and kills the person by suffocating him.
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It is because it uses up all the oxygen in the room and increases CO2.if we keep breathing co2 it can cause us diseases
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