Emergency medical personnel (firefighters and ambulance personnel) have higher levels of lifetime PTSD symptoms than the general population. Historically this has been attributed to the number of exposures to traumatic incidents, called the dose effect, but recent literature has suggested that there is a complex web of variables that affect an individual's experience of trauma. Through an interpretive review of the literature this dissertation takes the concepts supported by empirical research and organizes them into an integrated theoretical structure. With ecological psychology at the core, the integration uses Living Systems theory as a structure with which to organize and explore the different interactive ways that the environment in which emergency medical personnel live affects their experience of stress, coping skills, and overall resilience. At each level in the system, the effects on an individual's experienced or perceived resources are evaluated using Conservation of Resources theory. By using this theory, resources from variables as broad as global recessions to as precise as nutrition and brain functioning can be explored in a cohesive way that shows the interplay of resources across the system and the acute effects on individuals in the emergency medical field. This dissertation uses this model to identify junctures at each of the eight levels of living systems where resources can be addressed in a clinically relevant way. Limitations of current research data and implications for future research and clinical interventions are discussed.