Analysis of Accidents and Learning from them

Investigating and researching incidents in order to determine the chain of events and effective causes in the occurrence of each event is an important and sensitive part of the Process Safety Management Scheme, so that the necessary corrective measures can be set forth and implemented. Accordingly, in the OSHA process safety management program as well as CCPS, any event that has resulted in (or has the potential for) a catastrophic release of highly hazardous chemicals must be investigated and analyzed.

After the process of investigating the incident and collecting relevant evidence, the process of analyzing the incident begins. Accident analysis puts together all the necessary and sufficient events for the occurrence of the accident by observing the logical hierarchy and order of their occurrence. Analyzing the incident and learning from it is used to prevent similar incidents in the future. Accident analysis helps to identify the factors affecting the accident, the factors that, if identified, can lead to prevention of similar accidents in the future. On the other hand, the analysis of the factors affecting the occurrence of the accident takes time and requires expert people; in order to complete the chain of factors affecting the accident, it may require revisiting the scene of the accident and even the environments that were not directly related to the accident. This requires a broad perspective of the accident in order to identify all the hidden problems that caused it in the first place.

Identifying factors influencing the occurrence of an accident: During this process, the causes of the accident are identified. Generally, they are analyzed by dividing the causes into four categories.

- Direct causes
- Indirect causes
- Underlying causes
- Root causes

• Direct causes:
  Unwanted release of dangerous energy or substance during an accident. If the direct cause is known, then the equipment, materials, and facilities can be made safer by redesigning, by providing personal protective equipment the severity and rate of injuries can be reduced, and by training employees to inform them of dangerous conditions. In this way, they can protect themselves from dangers. Undoubtedly, identifying the direct cause of the accident can facilitate the understanding of the cause of the accident and the importance of dissipating the lessons learned from it.
• Indirect causes:
  The most obvious reason why an accident can occur is unsafe practices or conditions.
• Background causes:
  The underlying causes are the indirect causes of the accident and are divided into two categories: occupational and human factors.
• Root causes:
  Root causes are ones that, if corrected, prevent the reoccurrence of a given incident and similar ones. They may include several underlying and indirect causes. These causes have a higher order and instead of focusing on the direct and specific cause, encompass several problems.

Most of the accidents in the petrochemical industry have been analyzed with the aim of preventing similar accidents from happening, and reports of learning from them are shared in this section. In these reports, while specifying the root causes of the accident, the necessary measures to prevent the occurrence of the accident are provided.