Embodiments of the present invention are directed to a method and system for preventing ingestion of ambient air contaminated with possibly harmful, toxic, or flammable battery gases into a passenger compartment of a vehicle in the event of a battery failure. If an abnormal state is detected in a battery pack of the vehicle, the vehicle automatically switches the HVAC system to air recirculation mode, thereby preventing any toxic gas emitted from the battery pack from entering the passenger compartment.