The objective of this study is to assess main risk factors for volunteers mental health in general, and spontaneous volunteers mental health in particular, in order to provide intelligence to facilitate the integration of spontaneous volunteers in disaster and emergency response successfully in the future. The data is based on the evaluation of the work in practice of the pioneer program called Team Österreich, which integrated civilians into the Red Cross emergency response in the refugee camps and transit points in Austria during the migration movement in 2015, caused by the ongoing Syrian war. This was the largest operation of Team Österreich since its establishment in 2007. An online questionnaire, which assessed demographic and assignment related data, was created to identify the main stresses and needs on the ground. The questionnaire, which was distributed via email by the Red Cross Headquaters, included further the Impact of Event Scale Revised (Weiss and Marmar, 1997) to assess the volunteers stress levels, and the Sense of Coherence Scale 29 (Aaron Antonovsky, 1979) to assess the volunteers sense of coherence. The data was then used to examine different hypotheses regarding the stress impact on the volunteers based on different factors, namely their role as spontaneous or regular volunteers, the amount of received psychosocial support, their sense of coherence, their gender, marital status and education level. Results approved for sense of coherence, psychosocial support, gender and being a spontaneous volunteer as significant risk factors for volunteers.