OXIDIZING AGENTS FOR EMERGENCY POWER UNITS

In accordance with at least one aspect of this disclosure, an emergency power unit system for an aircraft includes a fuel cell system configured to generate power using a fuel and an oxidant, and an oxidant supply system fluidly connected to the fuel cell system to supply the oxidant to the fuel cell system via an oxidant supply line. The oxidant supply system is fluidly connected to an environmental control system of an aircraft.