(105c) Addressing Human Error In Systemic Failures: A Case Study Combining Incident Investigation Approaches

This case study demonstrates an effective incident investigation approach to identify systems-related root causes. The premise is simple: ?What people do makes sense to them at the time.? The approach combines human error concepts and human factors analyses used in both the aviation and chemical industries (refer to J. Reason, T. Kletz and CCPS publications) with the concepts described by S. Dekker in ?The Field Guide to Understanding Human Error.? The combined approach helps define and eliminate ?hindsight bias? (the investigator's bias that exists because of the known bad consequence). The case study's human error mistake was simple and straightforward; however, it failed to capture the role multiple previous decisions played in the incident. The team's original recommendation to prevent recurrence: retrain everyone on the procedure (in essence, the ineffective ?be more careful next time? tone). However, a deeper Process Safety Management (PSM) systems-related issue was uncovered by continuing the probe using the human error "root cause" as the starting point of the investigation. As Dekker notes, this is the point where the real, and more difficult to address, systemic issues are found. This case study showed how poor communications between the different people involved with engineering design, contractor fabrication, equipment inspection and subsequent site installation caused the incident. The team's recommendation: link the separate MOC, PSSR and Mechanical Integrity Quality Assurance-related efforts together, especially with ensuring an inspection step for ?replacement-in-kind? equipment. In conclusion, the combined approach helps the team better understand the timing and conditions of the event, better understand why people make the decisions they make at the time the event unfolds, and ensures that systemic root causes are discovered so that more appropriate, systems-related preventive measures are chosen and implemented.