In case of emergencies the population in danger should be alarmed so individuals can take action to get or remain out of danger. For alarming the population the means available are limited. Many countries have outdoor sirens. They operability however is limited since the siren has only one implicit instruction to the population. This instruction should moreover be known. The Safety Science Group has been involved in studying the potential effectiveness of alarming and informing the population via mobile phone messages since 2004 in national and EU context. In the course of 2012 this technology will come available for citizens’ alarming in The Netherlands. This paper discusses the field of citizens’ alarming and the type of technologies available to communicate to the population. This framework is relevant for understanding how one should asses a new technology from a safety point of view. One of the challenges for the new alarming service is the composition of a short message to alarm the population via their mobile phone, which is complete, relevant and correct for situation. This is new field which is recently being explored. We explain amongst others how the not yet known disaster is dominant for the message content and explain how a message can be composed. Results from workshop with experts from the emergency rescue services are discussed. We rounds off arguing dilemmas in order to get to effective citizens’ alarming via the new service.