This paper explores the design and evaluation of a trust model to establish trust management in an open source collaborative information repository for an emergency response environment. The proposed model is an instantiation of the SECURE framework and it is based on the characteristics of trust defined by recent information systems research. Evaluation of the model is based on a case study of a drill conducted by a city in Southern California. The results suggest that the proposed model might be useful to provide timely action plans for specific types of incidents based on the level trust and risk. However, a common terminology among involved organizations must exist prior to implementing the proposed model. In addition, information is volatile in an emergency response environment and rapid changes in conditions influence the consensus among entities. Therefore, verifying the accuracy of the emergency information used by the proposed model is essential to establish trust management in this particular context.