To estimate the risks associated with the use of hydrogen in the distribution network and the built environment compared to the use of natural gas, it is important to know the differences in chances and consequence. The chance relates in particular to the probability of a dangerous situation occurring; the consequences can be expressed in damage caused by that hazardous situation (typically fire or explosion). Mitigating measures are aimed at reducing the chance of a dangerous situation arising or lowering its consequences. To this end, the Hydelta programme defines the 'Hydrogen and Safety' work package in which the main objective is formulated as: Identifying the risks of hydrogen leaks in homes and in the distribution network and defining mitigating measures on the basis of the risks. To answer this main question, this report relies heavily on previously published work from the United Kingdom (UK) where similar research has been conducted. In the first phase of the research, an analysis was made of the ... : Dit project is medegefinancierd door TKI Nieuw Gas | Topsector Energie uit de PPS-toeslag onder referentienummer TKI2020-HyDelta. ...