Carrying out an investigation

A thorough investigation into an accident will help you establish the real cause or causes, and enable you to identify the changes needed to prevent a recurrence or similar accidents.

There are normally three types of causes to an accident:

1. immediate causes: the agent of injury or ill-health (the blade, the substance, the dust, etc.);
2. underlying causes: unsafe acts and unsafe conditions (the guard removed, the ventilation switched off, etc.); and
3. root causes: the failure from which all other failings grow, often remote in time and space from the adverse event (e.g. failure to identify training needs and assess competence, low priority given to risk assessment, etc.).

Your investigation should aim to find all three and focus on the root cause(s) when considering the remedial actions.

For full details see the HSE publication HSG245 Investigating accidents and incidents.

Appendix 5 in HSG65 Successful Health and Safety Management also provides a number of aspects to consider to help ensure that your investigation is both thorough and appropriate. The main points are summarised below.

Investigations into accidents should be properly planned and organised to get the best result (i.e. a true understanding of the root cause). A written procedure will help focus attention on what needs to be done and should cover:

• the types of accident to be investigated:
  • those where the potential severity of injuries and the likely frequency are both significant or worse/higher; and
  • you should also investigate near misses in this category.
• those involved in and those leading the investigation:
  representatives from management and employees should both be involved in the investigation (According to HSG245, ‘it has been found that where there is full co-operation and consultation with union representatives and employees, the number of accidents is half that of workplaces where there is no such employee involvement.”)
  • the manager of the area where the accident/incident occurred should lead the investigation with assistance from your competent person, as required.
• when the investigation should start:
  • as soon after the event as is reasonable, as the memory for details and motivation for the investigation both fade with time; and
  • depending on the magnitude and immediacy of the risk involved (e.g. a major accident involving an everyday job will need to be investigated quickly).
• the format to be used, this includes:
  • information gathering;
  • analysis;
  • risk control measures; and
  • action plan and implementation.

For more information, see Format for an investigation