Accidents investigating

Accident investigation indicates that there are often many individual causes to an accident, and that a series of incidents occur simultaneously to cause the accident. The following figure is called the safety triangle", and shows the approximate ratios of occurrence of accidents with different severities. This is based on industrial statistics. 

Procedures are written to ensure that activities are performed in a systematic way. Accident investigation shows that the majority of accidents occur because procedures are not followed, and this contributes mostly to the base of the safety triangle introduced at the end of Section 4.1. 

U.S. Government Printing Office, EPA/OSHA Joint Chemical Accident Investigation Report, Napp Technologies, Inc. Lodi, New Jersey. EPA 550-R-97-002. October 1997. 

Table 10.34 Data to record during accident investigation...

The employer investigates incidents that result in, or could result in, a catastrophic release of highly hazardous chemicals. An incident investigation is initiated as soon as possible, but before 48 hours following the incident. An incident investigation team is established to consist of one or more experts in the process involved, and accident investigation. The report prepared at the conclusion of the investigation includes at a minimum ... 

In addition to these formal studies of human error in the CPI, almost all the major accident investigations in recent years, for example, Texas City, Piper Alpha, Phillips 66, Feyzin, Mexico City, have shown human error as a significant causal factors in design, operations, maintenance or the management of the process. Figures 4.4-1 and 4.4-2 show the effects of human error on nuclear plant operation. 

Previously, the facility had several mullimillion dollar accidents, and near misses. After each accident, investigations were made and corrective actions taken. However the large fire precipitated a risk evaluation of the entire mining complex to find latent accidents. 

Bulletin 3/96, Air Accident Investigation Branch, Defence Research Establishment, Famborough, UK. 

Baker and his colleagues (1983) compared the Strehlow et al. (1979) curves to experimental data, then applied them in research programs, accident investigations, and predictive studies. They developed the methods for use of Strehlow s curves. 

Maintenance (Mechanical Integrity) —Pre-Startup Review —Management of Change —Safety Audits — Accident Investigation... 

One of the origins of this view of error and accident causation is the theory of accident proneness, which tried to show that a small number of individuals were responsible for the majority of accidents. Despite a number of studies that have shown that there is little statistical evidence for this idea (see, e.g., Shaw and Sichel, 1971) the belief remains, particularly in traditional industries, that a relatively small number of individuals accoimt for the majority of accidents. Another element in the emphasis on individual responsibility has been the legal dimension in many major accident investigations, which has often been concerned with attributing blame to individuals from the point of view of determining compensation, rather than in identifying the possible system causes of error. 

The focus of this chapter has been on proactive application of these analytical methods such as safety audits, development of procedures, training needs analysis, and equipment design. However, many of these methods can also be used in a retrospective mode, and this issue deserves further attention in its own right. Chapter 6 describes analytical methods for accident investigations and data collection. 

Typically, the first phase of a comprehensive accident investigation process will involve describing the way in which the hardware, the chemical process, individual operators and operating teams are involved in the accident process. This is the domain of the structural analysis techniques and the technical analysis of the chemical process which gave rise to the accident. Analyses of human error will primarily address the interactions between hardware systems and individuals or operating teams (the first two layers... 

Planned changes should be documented as part of a formal change monitoring process (for example via a quality assurance system). Unplanned changes should be identified during the accident investigation process. 

Ferry, T. S. (1988). Modem Accident Investigation and Analysis (2nd edition). New York Wiley. 

Accident investigation Procedures - to e aluatc any EHS accidents that occur, with the focus on prevention of a recurrence... 

Sulphuric acid at 93% was added to p-nitrotoluene. The temperature reached 160°C due to a failure of the thermal control system. The sulphonic acid formed decomposed violently at this temperature. The post-accident investigation showed that the decomposition started between 160 and 190 C. In fourteen minutes the temperature rose to 190-224°C and in one minute and thirty seconds to 224-270°C. A large volume of gas was then released during the eruption. The phenomena caused by the decomposition of nitrated derivatives in the presence of sulphuric acid will be addressed several times. What these incidents have in common is the formation of large carbonised volumes. This phenomenon is common with sulphonic acids. The nitro group role is to destabilise intermediate compounds and final compounds and to generate... 

Furfural was added drop by drop to a solution of 10% of hypochlorite at 20-25 C. At the end of this operation a violent detonation destroyed the equipment. The post-accident investigation showed that during the handling, pH decreases slowly down to 8.5, then suddenly to pH 2. At the same time the temperature rises suddenly to 70°C. The study showed that the same is true for benzaldehyde. 

The accident investigation evidence showed that this safe procedure was not followed specifically, the product takeoff valve was removed, the DEMCO valve was in the open position, and the lockout device was removed. This scenario was a serious violation of well-established and well-understood procedures and created the conditions that permitted the release and subsequent explosion. 

M. he investigation of accidents and near misses (that is, close calls) provides opportunities to learn how to prevent similar events in the future. Accident investigations, including detailed descriptions and recommendations, are commonly shared within the chemical industry. Many professionals believe that this sharing of information about accidents has been a major contributor to the steady improvement in safety performance. 

The number of relevant facts accumulated in an accident investigation is usually limited. Further investigation usually cannot uncover additional facts. A deeper analysis of the facts, however, often leads to new conclusions and recommendations. This deeper analysis is, for example, similar to a brainstorming session to develop new applications for a common house brick. New and interesting applications will continue to surface. 

T. Kletz, Layered Accident Investigations, Hydrocarbon Processing (November 1979), pp. 373-382 and T. Kletz, Learning from Accidents in Industry (Boston Butterworths, 1988). 

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