Abstract. Emergency management becomes more challenging in international crisis episodes because of cultural, semantic and linguistic differences between all stakeholders, especially first responders. Misunderstandings between first responders makes decision-making slower and more difficult. However, spread and development of networks and IT-based Emergency Management Systems (EMS) has improved emergency responses, becoming more coordinated. Despite improvements made in recent years, EMS have not still solved problems related to cultural, semantic and linguistic differences which are the real cause of slower decision-making. In addition, from a technical perspective, the consolidation of current EMS and the different formats used to exchange information offers another problem to be solved in any solution proposed for information interoperability between heterogeneous EMS surrounded by different contexts. To overcome these problems we present a software solution based on semantic and mediation technologies. EMERGency ELements (EMERGEL) (Fundacion CTIC and AntwortING Ingenieurbüro PartG 2013), a common and modular ontology shared by all the stakeholders, has been defined. It offers the best solution to gather all stakeholders' knowledge in a unique and flexible data model, taking into account different countries cultural linguistic issues. To deal with the diversity of data protocols and formats, we have designed a Service Oriented Architecture for Data Interoperability (named DISASTER) providing a flexible extensible solution to solve the mediation issues. Web Services have been adopted as specific technology to implement such paradigm that has the most significant academic and industrial visibility and attraction. Contributions of this work have been validated through the design and development of a cross-border realistic prototype scenario, actively involving both emergency managers and emergency first responders: the Netherlands–Germany border fire.