The Prince William Sound Risk Assessment

Reviewer: John W. Fendrich

The efforts of a consultant team in risk assessment from George Washington University, Rensselaer Polytechnic Institute, and Del Norske Veritas are examined in this paper. A steering committee, which was formed in 1995, funded the consultant team. The steering committee was composed of representatives from oil shipping companies, a citizen advisory committee, and the United States Coast Guard, all which have interests in the Prince William Sound (PWS) region of Alaska. The steering committee was formed out of concern for the effectiveness and benefits of existing and proposed risk-intervention measures regarding the PWS oil transportation and ecosystem six years after the March 24, 1989 Exxon Valdez grounding and oil spill on Bligh Reef of PWS. A brief introduction to risk assessment and management in maritime transportation is provided in the paper. Using the technique of probalistic risk assessment, the consultant team constructed an accident probability model, which is described. The model was developed using some ideas from previous risk assessment models, plus some innovative, ad-hoc, techniques, especially for estimating PWS human-error conditional probabilities for incidents, given PWS human-errors. Following this exposition and information, the paper presents the results of the risk assessment, and the contribution these results made to the steering committee work, the report, and the continued safe use of the PWS for oil distribution. There is also a section on the validation of the risk assessment model developed. The paper states that, using the risk assessment model, it was estimated that the accident frequency had been reduced 75 percent since the Exxon Valdez incident, and additionally, there had a been a further reduction in accident frequency as result of the PWS risk assessment of 68 percent. The specific details of the actions taken based on the PWS risk assessment and that contributed to these latter reductions are discussed. Finally, the paper discusses the benefits of the risk-assessment process, including testimonials of representative views from members of the steering committee to which the consultant team made frequent reports during the steering committee meetings. One benefit of note was the risk assessment model used to get the diverse interests represented in the steering committee to cooperate and meet the committee's objectives of identifying and evaluating the risks of oil transportation in PWS and of identifying, evaluating, and ranking proposed risk-intervention measures. The understanding of system risk was a major benefit to the report of the steering committee and its results. The contribution of the paper to people working with computer machinery is as an example of the risk assessment process applied to a highly critical and visible system in current society. The example and ideas of the paper may contribute to the greater use of risk assessment in constructing new, critical, and less-visible systems that are based on the use of computing machinery. Online Computing Reviews Service