Purpose: The Ebola Virus Disease (EVD) outbreak was the most severe public health emergency in modern times. The economic impact of outbreaks has mostly been analysed at the macroeconomic level. Conversely, we aimed to estimate the economic costs of preventive measures of the outbreak to an extractive firm, ArcelorMittal, using data in the outbreak region from March 2014 to December 2015. ArcelorMittal is the worlds largest steel producer and particularly important in West Africa, where the extractive industry is economically crucial. Methods: Qualitative methods, in-depth interviews and focus group discussions, were used to investigate the events and channels of impact of the outbreak on the firm, as perceived by employees and contractors. Quantitative data regarding these costs was also collected. Retrospective cost analysis estimated the actual cost of preventive methods adopted. Results: Most respondents indicated the largest cost impact was suspension of Phase II expansion, a series of projects designed to increase iron ore production in Liberia. The next largest cost was the preventive measures adopted to counter disease spread. Total costs incurred for adopting preventive measures was USD 10.58-11.11 million. The overall direct costs of preventive measures adopted within the fence shared 30-31% of the total costs incurred. The share of external donation supporting humanitarian response was 11-12% of the total costs, followed by 7-12% of relational costs. Conclusions: The firms response during the EVD outbreak focused on its employees and operations, which was later expanded to the wider community and then in supporting the international humanitarian response.