OBJECTIVE: To evaluate the precipitants, subject characteristics, nature and outcomes of unarmed threats in the ED. METHODS: A 12 month prospective survey of security codes precipitated by an unarmed threat (Code Grey). RESULTS: Data were collected on 151 subjects. The Code Grey rate was 3.2/1000 ED presentations. They were most frequent on Saturday and in the late evening/early morning. There were verbal or physical threats of violence made to staff on 104 occasions (69%, 95% confidence interval [CI] 61-76) and a perceived threat of patient self-harm on 114 occasions (76%, 95% CI 68-82). Median time to be seen by a doctor was 8 min (interquartile range [IQR]: 2-21 min) and median time from presentation to Code was 59 min (IQR: 5-222 min). Sixteen subjects (11%, 95% CI 6-17) had a history of violence, 45 (30%, 95% CI 23-38) were affected by alcohol, 25 (17%, 95% CI 11-24) had used illicit drugs and 79 (52%, 95% CI 44-60) had a significant mental illness contributing to the Code Grey. Seventy-one patients (47%, 95% CI 39-55) required psychiatric admission, 49 (79%, 95% CI 66-88) involuntarily. CONCLUSION: Acutely agitated subjects pose a threat to themselves and the staff caring for them. The reason for the agitation is multifactorial and the majority arrive in a behaviourally disturbed state requiring early intervention. The times most likely to result in a Code Grey coincide with least available resources: ED and hospital risk management policies must account for this. A coherent approach by ED to this population is required to optimize patient and staff outcomes.