Many deaths from home fires are the result of burns and panic, but most are caused by deadly smoke and gases. These fatal fires are often caused by such careless acts as throwing away a lighted match or cigarette, allowing rubbish to pile up, overloading electrical wires, or misuse of heating and cooking equipment. Few families go to bed at night without first checking to make sure that the doors and windows are locked, but they overlook a very basic fire safety rule. This rule states that people should sleep with their bedroom doors closed. Nighttime fires are most serious because the family is asleep and the discovery of fire is usually too late. A closed bedroom door gives extra protection by delaying the gases and fire, thus giving the family a few minutes to escape. At the first sight of fire in a home, it is necessary for everyone to get out of the house, especially children and elderly persons who may need help. Not everyone flees(逃跑) quickly from a burning home. Children often panic and hide in closets or under beds. Being prepared or knowing what to do in case fire breaks out can mean the difference between life and death. All members of the family should know certain basic steps. Everyone should know an escape route and second route from each room in the house. Very young children and old persons should receive careful thought when mapping out(制订) family escape plans. Both groups will need special help in escaping from home fires. A family 'should deter mine a way in which any members can sound an alarm. It is likely that fire may block hallways and prevent a person from reaching other bedrooms. Family members should be taught not to waste time getting dressed or collecting valuable possessions. Speed is necessary in escaping from fire. Most deaths from fire are caused by ______.