BACKGROUND: Unknown and unpredictable situations cause emergency medical service (EMS) providers to experience various stressful factors. These factors are affected by sociocultural conditions and expectations of the casualty and affect EMS providers' performance and health at the incident scene. The present study was conducted to explore EMS providers' perception of stressful and health-threatening factors in emergency missions.METHOD: This qualitative conventional content analysis was conducted in 2020. The participants included 16 EMS providers working at the Emergency Medical Services Department in Hamadan Province, Iran. The participants were selected using purposive sampling and underwent semi-structured interviews until data saturation. Data were analyzed using the Graneheim and Lundman method.RESULTS: Analysis of the interview data yielded six subcategories (i.e., incident scene hazards, violence-related injuries, physical injuries caused by patient care/handling, ambulance crash-related injuries, emotional impact of patients' suffering and ailments, and highly stressful missions), two main categories (i.e., physical injuries and psychological tensions), and a theme of occupational injuries.CONCLUSIONS: According to the results, in addition to having concerns about caring for patients and saving the injured, EMS providers also worry about potential threats to their own health. The present study identified and described some major stressors in emergency missions. Thus, for a better and more effective efficiency, the present study results can be used to reduce or modify stressors in EMS providers.KEYWORDS: stress, emergency medical service, qualitative study