A flow battery system includes a safety system and method for maintaining a safe operation of a flow battery and the flow battery system. The system and method are configured to provide for the safe operation of flow batteries with chemistries involving hydrogen (H.sub.2) gas. Oxygen sensors and other temperature and gas concentration sensors are placed at active material storage tanks and connected to an electronic control unit. Feedback from the sensors is used to ensure that the battery system appropriately and rapidly responds to the development of conditions that might lead to volatility. These responses include discontinuing battery operation, engaging pressure relief valves, and engaging oxygen removal systems.
GOVERNMENT RIGHTS NOTICE
 This invention was made with government support under DE-AR0000137 awarded by the Department of Energy Advanced Research Projects Agency-Energy. The government has certain rights in the invention.