Which of the following is a common cause of fire in residential buildings?

Natural gas leaks are a common cause of fires in residential buildings because they can lead to explosions or flash fires when the gas is ignited. Natural gas is highly flammable, and if there is a leak within a home, it can accumulate and create a dangerous situation. When a spark from an electrical appliance, pilot light, or any open flame ignites the trapped gas, it can result in significant fire hazards, potentially causing extensive damage, injury, or even fatalities.

This risk underlines the importance of proper installation and maintenance of gas appliances and detection systems in homes. Homeowners are often encouraged to install carbon monoxide detectors and regular inspections of gas lines to prevent such potentially catastrophic incidents.

In contrast, while heat exhaustion and water leaks pose risks in a residential setting, they are not direct causes of fires. Heat exhaustion is a medical condition resulting from the body overheating and does not involve fire. Water leaks can cause damage and mold issues but generally do not lead to fires. Air conditioning units, while they can malfunction and create electrical hazards, are not as common a direct cause of fires compared to natural gas leaks.