An increase in use of hydrogen for energy storage and clean energy supply in a future energy and mobility market will strengthen the focus on safety and the safe handling of hydrogen facilities. The ability to simulate the whole chain of physical phenomena that may occur during an accident is mandatory for future safety studies on an industrial or urban scale. Together with the RWTH Aachen University, Forschungszentrum J lich (J LICH) develops numerical methods to predict safety incidents connected with the release of either LH2 or GH2, using the commercial CFD code ANSYS CFX. The full sequence from the release, distribution or accumulation of accidentally released hydrogen, till the mitigation of accident consequences by safety devices is considered. For specific phenomena like spreading and vaporization of LH2 pools or the operational behavior of passive auto-catalytic recombiners (PAR), in-house sub-models are developed and implemented. The paper describes the current development status, gives examples of the validation and concludes with future work to provide the full range of hydrogen release and recombination simulation.