The underestimated value of safety in achieving organizational goals : cast analysis off the Macondo accident

Abstract

On April 20, 2010, an explosion in the rig Deepwater Horizon performing drilling operations on the Macondo Prospect Well, in the Gulf of Mexico, led to the largest oil spill in the history of the petroleum industry. Eleven crewmembers lost their lives and around 4.9 million barrels of oil were discharged into the ocean until the continuous subsea blowout of the well was contained in September 19, 2010. Given the magnitude and the complexity of the accident, several safety analyses have been proposed by the international community at different levels of the system involved in the accident. Most of these studies use accident analysis techniques based on chain-of-event models, whose main objective is to identify root-causes. However, while this approach describes physical phenomena accurately, it does not explain the role of organizational and socio-economical factors, human decisions, or design inaccuracies in accidents in complex, adaptive, and tightly coupled systems like Macondo. In response to this need, N. Leveson developed the new accident-analysis technique Causal Analysis Based on System Theory (CAST), based on her model System-Theoretic Accident Model and Processes (STAMP). In STAMP accidents are not treated as chain of failure events, but as complex processes that result from a large variety of causes including component failures and faults, system design errors, unintended and unplanned interactions among system components, human operator errors, flawed management decision-making, inadequate controls and oversight, and poor safety culture. This thesis presents management recommendations based on a CAST analysis of the Macondo Accident. The goal is to help the oil and gas offshore drilling community achieve safer operations and understand the value of systems safety in achieving organizational goals.