Background: A black system event (BSE) is a large scale black-out where there is a loss of a major power supply. From a health perspective a BSE may disrupt essential equipment within a health service that may be necessary for providing care. There is a paucity of literature relating to BSE and their impact on emergency departments (EDs). Aim: The research aimed to understand the impact of a BSE on ED clinicians in South Australia. Method: This research used a cross sectional survey design by surveying South Australian ED clinicians who worked during the BSE. Data was collected via a survey with closed and open questions. Quantitative data was analysed using descriptive statistics and qualitative narrative was analysed using a thematic analysis. Results: Surveys were returned from 42 nurses and 7 doctors. The respondents were mostly female and most worked in a metropolitan ED. The majority of participants had undertaken some form of disaster education and/or training, despite never been involved in a major incident or disaster. A lack of lighting radiography systems not working, communication systems not working and patient tracking systems not working were the most common ways the ED was impacted. Conclusion: This research is the first to focus exclusively on the impact of a BSEs on EDs in Australia. Emergency departments are encouraged to educate and train staff to be prepared for BSEs, test electrical systems and improve communication with the ED.