A fire prevention and extinguishing system for an aircraft or other passenger transportation vehicle comprising at least one compartment (14, 14A, 14B, 14C, 14D, 14E) located on-board the vehicle, comprising: (a) a fuel cell system; (b) a source of inert gas comprising an oxygen depleted air output of the fuel cell system; (c) a conduit (28, 28A, 28B, 28C, 28D, 28E) configured to convey inert gas from the source of inert gas to the compartment (14, 14A, 14B, 14C, 14D, 14E) to reduce a risk of fire ignition in the compartment or to facilitate extinguishing of fire within the compartment (14, 14A, 14B, 14C, 14D, 14E); and (d) a valve (34, 34A, 34B, 34C, 34D, 34E) or other regulator configured to control a flow level of inert gas from the source to the compartment (14, 14A, 14B, 14C, 14D, 14E), the system further comprises: a heat exchanger associated with the compartment (14, 14A, 14B, 14C, 14D, 14E); one or more sensors (36,36A,36B,36C,36D,36E) configured to provide information about whether the compartment (14, 14A, 14B, 14C, 14D, 14E) is subject to conditions that may correspond to a risk or presence of fire; a controller; one or more processors in communication with the controller; and memory including instructions that, when executed by the one or more processors, cause the one or more processors to: in response to information received from the one or more sensors (36,36A,36B,36C,36D,36E) indicating that conditions in the compartment (14, 14A, 14B, 14C, 14D, 14E) are indicative of fire or imminent ignition therein, cause the heat exchanger to activate so as to transfer heat away from the compartment (14, 14A, 14B, 14C, 14D, 14E), in response to information received from the a sensor indicating that conditions in the compartment (14, 14A, 14B, 14C, 14D, 14E) are indicative of fire or imminent ignition therein, cause the valve (34, 34A, 34B, 34C, 34D, 34E) or other regulator to direct inert gas from the source to the compartment (14, 14A, 14B, 14C, 14D, 14E). (a) a fuel cell system; (b) a source of inert gas comprising an oxygen depleted air output of the fuel cell system; (c) a conduit (28, 28A, 28B, 28C, 28D, 28E) configured to convey inert gas from the source of inert gas to the compartment (14, 14A, 14B, 14C, 14D, 14E) to reduce a risk of fire ignition in the compartment or to facilitate extinguishing of fire within the compartment (14, 14A, 14B, 14C, 14D, 14E); and (d) a valve (34, 34A, 34B, 34C, 34D, 34E) or other regulator configured to control a flow level of inert gas from the source to the compartment (14, 14A, 14B, 14C, 14D, 14E), a heat exchanger associated with the compartment (14, 14A, 14B, 14C, 14D, 14E); one or more sensors (36,36A,36B,36C,36D,36E) configured to provide information about whether the compartment (14, 14A, 14B, 14C, 14D, 14E) is subject to conditions that may correspond to a risk or presence of fire; a controller; one or more processors in communication with the controller; and memory including instructions that, when executed by the one or more processors, cause the one or more processors to: in response to information received from the one or more sensors (36,36A,36B,36C,36D,36E) indicating that conditions in the compartment (14, 14A, 14B, 14C, 14D, 14E) are indicative of fire or imminent ignition therein, cause the heat exchanger to activate so as to transfer heat away from the compartment (14, 14A, 14B, 14C, 14D, 14E), in response to information received from the a sensor indicating that conditions in the compartment (14, 14A, 14B, 14C, 14D, 14E) are indicative of fire or imminent ignition therein, cause the valve (34, 34A, 34B, 34C, 34D, 34E) or other regulator to direct inert gas from the source to the compartment (14, 14A, 14B, 14C, 14D, 14E). in response to information received from the one or more sensors (36,36A,36B,36C,36D,36E) indicating that conditions in the compartment (14, 14A, 14B, 14C, 14D, 14E) are indicative of fire or imminent ignition therein, cause the heat exchanger to activate so as to transfer heat away from the compartment (14, 14A, 14B, 14C, 14D, 14E), in response to information received from the a sensor indicating that conditions in the compartment (14, 14A, 14B, 14C, 14D, 14E) are indicative of fire or imminent ignition therein, cause the valve (34, 34A, 34B, 34C, 34D, 34E) or other regulator to direct inert gas from the source to the compartment (14, 14A, 14B, 14C, 14D, 14E).