Conducting an Effective Incident Investigation

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The main objective of an investigation is prevention. A good investigation aims to establish a series of events that should have taken place and compares it to what actually happened to identify areas that need changing. A number of important skills are involved in conducting an effective investigation. An effective investigation can help you prevent similar incidents and future injuries. Always keep in mind that effective incident investigation means fact-finding, not fault-finding.

Overview of an incident investigation process

Select an investigation team

The type of investigation conducted depends on the seriousness or complexity of the incident, but it is best done as a team so all parties can contribute their skills and expertise to achieve the best result. Investigators are collectors of evidence and must base their conclusions on that evidence. Take the time to choose the right people to conduct the investigation. The following people should be considered for the team:

  • Safety Officer/Manager
  • safety representatives where they exist
  • line manager/supervisor
  • person/s from the worksite
  • people with the relevant knowledge

Train your investigation team

Training your team in advance can help ensure your investigations are effective, your people have the necessary skills, and your people understand their roles before to being faced with an actual incident.

Investigation procedures

Investigation procedures need to be systematic. For any investigation the team should:

  • act as soon as possible after the incident
  • visit the scene before physical evidence is disturbed
  • not prejudge the situation
  • not remove anything from the scene
  • enquire if anyone else has moved anything
  • take photographs and/or sketches to assist in reconstructing the incident.

What to look for

Build a chain of events to identify all the causes. For the investigation to be successful it is necessary to establish the following information:

1. Events leading up to the accident


  • the system of work being carried out and the adequacy or suitability of that system for the job
  • the instructions and/or training given for the work
  • any variation from instructions or standard work practices and the reasons for such variation
  • the workplace conditions, such as lighting, floor surfaces, stair treads and handrails, warning signs, temperature and weather (if the incident occurred outside)
  • the exact location of the incident with sufficient detail for the spot to be readily identified by others reading the report
  • the materials in use or being handled
  • the type of transport or equipment in use
  • whether adequate supervision was provided.

2. Facts of the incident itself


  • the state of the system and the actions that occurred at the time
  • the people directly and indirectly involved
  • the tools, equipment, materials and fixtures directly connected
  • the time the accident or incident occurred.

3. Facts regarding what occurred immediately after the incident


  • any injuries or damage resulting directly from the accident
  • the people involved, including those rendering aid
  • any problems in dealing with the injuries or damage, for example faulty extinguisher or if isolation switch difficult to locate.

4. Essential factors and causes

To conduct an effective accident/incident investigation, it is essential to look for the design, environment/work process, and behavioural components, such as plant, procedures and people, rather than trying to isolate a single cause.

i. Design components:

  • Poor systems design may result in exposure to hazards such as:
  • unguarded dangerous parts of machinery
  • ineffective safety devices
  • provision of makeshift plant, equipment and tools
  • inadequate ventilation.

ii. Environmental components/work processes:

How people function in the work environment depends on what they experience in it. Environmental factors may be both physical and social. The way in which people do the job, the procedures they follow and the work process are important factors in incident investigation. Poor work process may lead to hazard exposure.

iii. Behavioural components:

Examples include misuse of safeguards, improper use of tools and equipment, disregard of cautionary notices, failure to wear personal protective equipment, horseplay and poor standards of housekeeping. Poor practices may indicate that improved communication, further training or some other action, such as supervision, are necessary

Establishing the facts

This list of questions may assist investigators to establish the facts. Note: Care must be exercised in obtaining answers to some of these questions, as the investigator could be accused of apportioning blame.

  • was injured?
  • saw the incident?
  • was working with the injured person/s?
  • had instructed and/or assigned the job?
  • else was involved?
  • has information on circumstances/events prior to the incident?
  • is the injury?
  • is the damage or loss?
  • was the injured person/s doing?
  • is the work process?
  • had the injured person/s been instructed to do?
  • tools were being used?
  • Machinery/ plant/ equipment was in use?
  • similar incidents have occurred previously? action had been taken to prevent recurrence?
  • safety rules were violated?
  • safe systems of work, permits to work, isolation procedures were in place? training had been given?
  • were the contributing causes of the accident/incident?
  • communication system was in use?
  • did the accident/incident occur?
  • did the damage become evident?
  • did the injured person/s start the job?
  • was an explanation of the hazards given?
  • did the supervisor last see the injured person/s?
  • was something seen to be wrong?
  • did the injury occur?
  • did communication fail?
  • was training not given?
  • were there unsafe conditions?
  • was the hazard not evaluated?
  • was the system of work inadequate or inappropriate?
  • was personal protective equipment not provided?
  • was protective equipment not used?
  • was there no safe system of work, permit to work or isolation procedure operating?
  • were specific safety instructions not given?
  • was the supervisor not consulted when things started to go wrong?
  • was the supervisor not there at the time?
  • did the accident/incident occur?
  • did the damage occur?
  • was the supervisor at the time?
  • were the witnesses at the time?
  • did the injury occur?
  • could the incident have been avoided?
  • could the injury have been avoided?
  • could the supervisor have prevented the incident?
  • could better design of plant or systems of work help?