Incident investigation case studies

The case study has documented the investigation and root cause analysis process applied to the hydrocarbon explosion that initiated the Piper Alpha incident. The case study serves to illustrate the use of the STEP technique, which provides a clear graphical representation of the agents and events involved in the incident process. The case study also demonstrates the identification of the critical events in the sequence which significantly influenced the outcome of the incident. Finally the root causes of these critical events were determined. This allows the analyst to evaluate why they occurred and indicated areas to be addressed in developing effechve error reduchon strategies. 

A. Kalelkar, Investigation of Large Magnitude Incidents Bhopal as a Case Study, Preventing Major Chemical and Related Process Accidents, Symposium Series No. 110, Institution of Chemical Engineers, Rugby, UK, 1988. 

In this case study, one of the strongest blast-generating BLEVEs to occur in the Mexico City incident (Section 2.4.3, Pietersen 1985), will be investigated. This BLEVE occurred a few minutes after the initial vapor cloud explosion and probably involved two 1600-m spheres. The spheres were probably 50% full at the time of the accident. 

The first case study describes the application of the sequentially timed event plotting (STEP) technique to the incident investigation of a hydrocarbon leak accident. Following the analysis of the event sequence using STEP, the critical event causes are then analyzed using the root cause tree. 

This case study concerns the events leading up to the hydrocarbon explosion which was the starting point for the Piper Alpha offshore disaster. It describes the investigation of the incident using the sequentially timed events plotting (STEP) technique. Based on the STEP work sheet developed, the critical events involved in the incident are identified and analyzed in order to identify their root causes. 

CASE STUDY 2 INCIDENT INVESTIGATION MISCHARGING OF SOLVENT IN A BATCH PLANT 307... 

CASE STUDY 2 INCIDENT INVESTIGATION MISCHARGINC OF SOLVENT 1 N A BATCH PLANT 309... 

Initially, the literature is searched for relevant data on the substance (physical-chemical properties, thermodynamics, incidents, case studies, and so forth). If insufficient data are available, the usual case, a systematic investigation procedure comprising three main subjects must be initiated for the material in question. 

The U.S. Chemical Safety and Hazard Investigation Board (CSB) has conducted detailed investigations into a few chemical reactivity incidents. Case studies and full investigation reports are available from the CSB (Washington, DC) or its website (www.chemsafety.gov). Extracts from three CSB publications (1998,2002a, 2002c) are given here. 

If incident case studies are periodically communicated to executives, they can help to reenforce the importance of doing things correctly. This typically translates into critical tasks that must he performed hy skilled workers and accoimtahility for those activities at an executive stewardship level. Such a commitment will carry over into incident investigation follow-up. 

The following case study describes the investigation work process for a hypothetical occurrence using a logic tree based multiple root-cause systems approach. An example incident investigation report follows the work process description. The example is intended for instructive purposes only descriptions of process equipment and conditions are not intended to reflect actual operating conditions. 

A Case Study of the Use of Electronic Networking for Incident Notification, Response, Mitigation, and Sharing, David W. Owens Legal Issues and Incident Investigations, Mark S. Dreux... 

That imaginary incident is the subject of a case study presented several times each year to groups of Dow supervisors and managers. The students represent a cross section of both experience and line and staff responsibilities. During a 2 -day Safety, Loss Prevention and Security Workshop, they will investigate the Dowville incident. 

Kalelkar, A. S. (1988). Investigation of large-magnitude incidents Bhopal as a case study. Paper presented at the Institution of Chemical Engineers Conference on Preventing Major Chemical Accidents, London, U.K.(May 1988). Retrieved March 13, 2007 from http //www.bhopal.com/CaseStudy.html... 

Mortality data are frequently used in cohort studies as opposed to incidence data because of the relative ease of obtaining information on deaths. In particular, the advent of the National Death Index has made mortality data more readily available. While all states maintain registries of incident cancer cases, many of the registries are relatively new and data quality can vary from state to state. Investigators conducting follow-up studies are required to comply with each state s requirements for use of the data. For cancers such as pancreatic cancer where survival is poor, mortality data is an excellent surrogate for the risk of the disease. For other cancers where the survival is much better, such as testicular cancer, mortality is a poor estimator of incidence. Table 15.5 describes the 5-year survival for several selected cancer sites for the period 1996-2004. As evident from the table, there is a considerable difference in survival rates for cancer of different sites. The 5-year survival rate for pancreatic cancer was only 5.1% compared to a survival rate of 98.9% for prostate cancer (SEER 2008). 

In the United States the U.S. Chemical Safety and Hazard Investigation Board (CSB) investigates chemical incidents. A web site provides a list of current investigations and a list of completed investigations. These case studies provide excellent analyses of the incidents that are often due to failures of safety systems and the lack of strong process safety. The CSB web site also includes videos illustrating incidents and these can be very useful in understanding how incidents have occurred in the past. 

Although relevant exercises have been conducted, and Cold War nuclear weapons programs provide validated analytic platforms, there have been no actual post-det terrorist incidents involving an IND or RDD to date. Consequently, no technical investigations in the contemporary embodiment of nuclear forensic analysis exist for an actual post-det situation, and all discussed case studies necessarily focus on interdicted, pre-det materials. (However, a nuclear accident that is perhaps exemplary of maximum-credible consequences of successful terrorist activities was the uncontrolled criticality and resultant explosion of the Soviet RBMK power reactor at Chernobyl in 1986.)... 

Committee duties can range from reviewing hazards reported and suggesting corrections, to conducting site surveys, to handhng incident investigations and follow-up of hazards. Some committees are advisory others have specific powers to correct hazards and, in some circumstances, to shut down unsafe operations [7]. Table 7-3 presents a sample employee participation case study for union sites. 

For how many incidents have the decisions affecting the sociotechni-cal workplace and work methods resulted in situations that are conducive to operator errors In Chapter 14, Incident Investigation Studies of Quality, it was said that in a substantial number of the investigation reports collected by this author, entries suggested that further inquiry should have been made into the design of the workplace or work methods. In many cases, the investigation reports pertained to incidents that occurred in error-provocative situations. Yet, often in those instances, only unsafe acts of employees would be recorded as the incident causal factors. 

The investigation lepoit into the case study found that the basic cause of the incident was a lack of communication between the Signaller and Driver of Run No. W700 about the proposed movement from the Down Main to the Up Main at Lawson. Some of the other contributing factors found by the Investi tion Team included ... 

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