The Need for a Probabilistic Risk Assessment of the Oil Tanker Industry and a Qualitative Assessment of Oil Tanker Groundings

Abstract : The culture, design, and operation of the maritime industry all contribute to create an error-inducing system. As oil tankers have become larger, the tolerance for error has decreased as the consequences have increased. Highly visible oil spills have made society more aware of the dangers inherent with transporting oil at sea. A probabilistic risk assessment (PRA) provides a formal process of determining the full range of possible adverse occurrences, probabilities, and expected costs for any undesirable event. A PRA can identify those areas that offer the greatest risk-reducing potential. Once the components with the greatest risk-reducing potential are identified, appropriate technology and management schemes can properly influence risk reduction. Humans contribute to high consequence accidents in the design, construction and operations phases of an engineering system. While human error is attributed to 80 percent of the marine accidents, a closer look reveals that many accidents attributed to human error are system errors. An application of a qualitative risk assessment is done for tanker groundings. A fault tree is developed to describe the top event of a tanker grounding. A number of well-known groundings are analyzed to test the utility of the grounding fault tree.