This study presents a reanalysis of FPSO (Floating Production Storage & Offloading) CSM (Cidade de São Mateus) accident, occurred in February 2015, in the post-salt of the Camarupim fields, in the Espírito Santo offshore area, using the FRAM (Functional Resonance Analysis Method) methodology, and based on technical-scientific materials such as books, articles and reports prepared by the companies involved in the accident and the Brazilian regulatory agency ANP (Agência Nacional do Petróleo, Gás Natural e Biocombustíveis). The purpose of this reanalysis is to seek elements, factors, characteristics and interactions that could not be well analyzed or evidenced using traditional risk assessment and accident investigation techniques, primally designed to analyze simple and linear systems. In order to have a coherent analysis between the accident and the complex sociotechnical systems involved, the FRAM methodology was chosen, as it comprehensively manages to analyze from simple to more complex systems. And in fact, with this reanalysis using the FRAM, it was possibleto perceive the influence of organizational elements, such as culture, in the entire accidental chain of the event. In addition, contractual pressures related to business, fear of hierarchical consequences and failures in decision making, at all levels, were also evidenced. The findings of this study highlighted the need of a broader approach for accidents involving high-tech industries, such as O&G and aerospace. In this sense, the FRAM enabled a more comprehensive and coherent analysis of the complexities of offshore oil production systems, notably in emergency situations, as was this accident. Comparisons between the traditional analysis methodologies, with the results obtained with the application of the FRAM, showed that there are elements contributing to the accidents that need to be considered, but that techniques limited to linear and simple systems still cannot cover this recognition. It was noticed that the greater the complexity of work systems, the greater the interaction and variability between personnel, equipment and systems, requiring, both for normal operation and for emergencies, analysis techniques and methodologies capable of recognizing the real complexities that take place in these socio-technical systems, especially aboard offshore oil platforms at sea.