NOVELTY - The method for discharging used operating media of a fuel cell in a fuel cell system, where some of the operating media are explosive, comprises analyzing the operating media from an operation space (27) of the fuel cell system before discharging by a sensor unit on explosibility. The discharging is carried out by a fan (29) arranged between the operation space and a mixing zone (32). A scavenging medium (28) is sucked through the operating space by the fan for aeration. The operating space mixes the scavenging medium with the operating media in the mixing zone to waste air (33).    USE - Method useful for discharging used operating media of a fuel cell in a fuel cell system.    ADVANTAGE - The method ensures efficient and safe discharging of used operating media of a fuel cell in a fuel cell system.    DETAILED DESCRIPTION - The method for discharging used operating media of a fuel cell in a fuel cell system, where some of the operating media are explosive, comprises analyzing the operating media from an operation space (27) of the fuel cell system before discharging by a sensor unit on explosibility. The discharging is carried out by a fan (29) arranged between the operation space and a mixing zone (32). A scavenging medium (28) is sucked through the operating space by the fan for aeration. The operating space mixes the scavenging medium before discharging, with the operating media in the mixing zone to waste air (33), which is discharged from the mixing zone. The flow of the waste air is determined from the flow of the scavenging medium regulated by the fan. The fan is regulated in dependence of the explosion capacity of the waste air. The used operating media is formed from a gaseous portion of cathode waste air and an explosibility gaseous portion of anode mixture. In the mixing zone, the explosibile, gaseous portion of anode mixture is mixed with the scavenging medium and the cathode waste air for waste air. The regulation of the fan is adjusted by periodic mixing of the anode mixture in the mixing zone. The flow of the scavenging medium is measured. A value of the explosion capacity of the discharged waste air is pulled up for operating the fuel cell system. A fluid portion of the used operating media is separated through a separator from gaseous portion of the used operating media in or above the mixing zone. The gaseous portion is conducted independent of operation of the fuel cell system. The mixed used operating media is conducted into the mixing zone. The fluid portion of the operating media is conducted and evaporated over a cooler with a thermally supervised evaporation arrangement in the mixing zone. An INDEPENDENT CLAIM is included for a device for discharging used operating media of a fuel cell in a fuel cell system.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of a method for discharging used operating media of a fuel cell in a fuel cell system.    Operating space (27)    Scavenging medium (28)    Fan (29)    Mixing zone (32)    Waste air. (33)