A methodology for Response Gap Analysis in offshore oil spill emergency management

In case of offshore oil spills, the success of emergency response largely depends on the meteorological and oceanographic conditions during and after the spill, which are expressed by a set of different environmental factors. A "gap" in the response may be caused by unfavourable environmental factors that could limit its effectiveness or even impede it. In this context, Response Gap Analysis (RGA) studies identify the environmental factors negatively influencing the emergency response in a given sea area and aim at assessing the percentage of time during which the response would be without success or impossible to deploy. In the present study, a new RGA methodology is described, based on 11 environmental factors. Different oil spill response strategies are considered: mechanical recovery, application of dispersants by vessel and by aircraft, and in-situ burning. A case-study is presented to demonstrate the methodology and discuss the outcomes obtained by its application.