Accident
Most of the deaths resulting from injuries are caused by fire accidents. Thus, accidental fires are one of the leading causes of unintentional deaths.  The main cause of death in fire incidents is burning, but inhalation of smoke and toxic gas causes death as well. Often the cause of the fire is very simple and unexpected, such as forgetting a candle near something flammable, defect in the hardware, or old electrical wires. So most of the large fires are caused by simple reasons.