We use the literature reporting prevalence and aetiology of post-traumatic stress disorder (PTSD) in first responders as a catalyst to discuss for organisations the policy implications for prevention and intervention of psychiatric morbidity. We searched PubMed and Google to identify studies and reports of mental health and behavioural problems in occupations including police, fire, and emergency service workers. The prevalence of PTSD ranged from 6 per cent to 32 per cent. Biological markers of PTSD, such as neuroendocrine activity, appear less useful than psychological markers, such as levels of hostility and self-efficacy, to predict PTSD. Prevalence of PTSD was generally less than that found among victims themselves, but higher than general community prevalence. Theoretically, if prevention and intervention strategies were working effectively, there should be a minimal rate of psychiatric morbidity attributable to these individuals' workplaces. Against this background, there is a case for routine screening on an annual basis for those at risk.