The main objective of this study is to define an emergency response team's location in a specific area based on the risk of refinery's plants. The Centre of Gravity and Hakini network methodologies are both used to define the team's location in a network based on index values and distance between locations. These methodologies are different with respect to one basic concept concerning the possibility of defining critical locations in the network in the first case and boundaries on the second case. The index in this case will be the frequency of hazardous events in each plant located in the network. The two methodologies will be implemented and the results will be assessed. A sensitivity analysis will be carried out, looking at specific elements such as alternative routes and population dislocation in case of accidents. Furthermore, the real historical data and usual data used in Brazil for hazardous events will be assessed to check the influence on the final results. A third methodology, the Monte Carlo simulation, will be carried out to check the emergency team's availability, safety reliability and number of expected unwanted events to support the final decisions and verify if the best location takes some influence in emergency attendance efficiency. The refinery case study will be carried out to define emergency response team location in a Brazilian refinery.