Abstract: A mouth piece supply valve control system which may be used in connection with mouth piece supply valve with a rebreather. An exemplary mouth piece supply valve control system may include a sensor operative to produce a sensor signal upon sensing a condition, a computer connected to the sensor that may produce a computer signal associated with sensor signal, a logic device operatively connected to the computer for receiving the computer signal, and an automatic actuator operatively connected to the logic device. The automatic actuator may be operatively coupled to a mouth piece supply valve that may be selectable between a first mode and a second mode and the automatic actuator may shift the mouth piece supply valve from the second mode to the first mode upon receipt of a logic device signal from the logic device.