Abstract: The Alarm Triggered Shut off Appliance System (ATSAS) relates to a safe control shut-off system for all utility appliances. It reduces the risks of fire and carbon monoxide poisoning before they occur by turning off utility appliances when the smoke detection/carbon monoxide alarms sound. As the alarms sound, the ATSAS automatically shuts off the appliance. This helps the occupants to take emergency action in the earliest stages of development of a fire/carbon monoxide breakout or prevents their occurrences when the occupant's direct action is impossible. The system has a tone decoder that is responsive only to the frequency range of the alarm's alert sound. The tone decoder prevents the system from being falsely activated by erroneous sounds. Once a smoke or gas leak occurs, the system detects the alert sound through its microphone, and energizes a relay or solenoid valve that turns off the supply line to the utility appliance.