Abstract: Systems and methods for monitoring and/or controlling fuel cell exhaust to provide a non-flammable exhaust stream. In some embodiments, operation of the fuel cell system is regulated to provide an exhaust stream that has a maximum flammability that is less than a predetermined fractional threshold of the lower flammability limit for the gases contained therein. In some embodiments, the systems and methods utilize the current produced by the fuel cell, or fuel cell stack, to monitor and/or regulate the flammability of the fuel cell exhaust stream. In some embodiments, the fuel cell system includes one or more controllers that are adapted to monitor the flammability of the exhaust stream from the fuel cell stack and/or to regulate the operation of the fuel cell system responsive thereto. In some embodiments, the operation and/or duty cycle of at least an anode purge valve is regulated or controlled responsive to the measured current.