Abstract: The subject application relates to a gas arrestor system(s) and/or methodology that facilitate sensing and shutting down a gas-burning appliance via a circuit that can perform both functions. In particular, the system and method can detect specific gases and at specific concentration levels by way of a sensory-power circuit. The circuit performs vapor detection and provides power to various ignition-related portions of the appliance. When gas or gas vapors are detected in the ambient air of the circuit and satisfy a threshold for that particular type of vapor, the circuit is shorted which results in a power loss to at least the ignition-related portions of the appliance. As a result, undesirable ignition of such vapors is mitigated.