An underground CO2 storage project is proposed under the village of Barendrecht, involving two nearly depleted gasfields. Because of the lack of sufficient knowledge of these kinds of storage projects, by the general public and also by the local politicians, several questions about the technical and geological aspects have been raised. In this report an effort is made to answer specific questions about the subsurface and its reaction to a CO2 storage project in a clear manner. These answers lead the reader through general CO2 information, followed by site specific details and also new calculations on the possibility and rate of CO2, that might escape from the reservoir in case of a dramatic subsurface failure. Based on our findings, as well as on previous research, we conclude that the threat of an accident is almost non-existent.