An incident investigation finds out what happened, why it happened and what will stop it happening again. Done well, it looks past the person closest to the event to the conditions, equipment, procedures and decisions that set it up. Provincial OHS laws require employers to investigate serious incidents, and many programs require investigation of near misses too.
What counts as an incident
Most programs use "incident" for any unplanned event that caused, or could have caused, injury, illness or damage. That includes:
- Injuries and occupational illnesses, from first aid cases to fatalities.
- Property and equipment damage.
- Releases of hazardous substances, fires and explosions.
- Near misses, where nobody was hurt but could have been. See near-miss reporting.
The depth of investigation should match the potential severity, not just the actual outcome. A dropped tool that missed someone's head deserves more attention than a paper cut.
Legal reporting comes first
Serious incidents must be reported to the provincial regulator, and often the scene must be preserved until an officer releases it. The list of reportable events and the timelines differ between Alberta, British Columbia and Ontario, and between provincial and federal jurisdiction. British Columbia, for example, sets specific timelines for preliminary and full investigation reports. Build your province's requirements into your procedure so that nobody has to look them up during an emergency. Separate reporting to the workers' compensation board is also required for many injuries.
The investigation step by step
- Make the scene safe. Care for injured people, control ongoing hazards, and secure the area. Do not put investigators at risk.
- Preserve evidence. Photograph the scene before anything moves. Note positions of equipment, tools and materials, the weather, lighting and housekeeping. Keep damaged parts.
- Assemble the team. Include someone trained in investigation, a supervisor who knows the work, and a worker representative or committee member. Avoid having only the supervisor of the affected crew investigate their own area.
- Interview witnesses separately and soon, while memories are fresh. Ask open questions, listen, and avoid suggesting answers. Explain that the aim is prevention, not blame.
- Collect documents. Procedures, hazard assessments, permits, training records, maintenance logs, inspection reports and any previous similar incidents.
- Build the sequence of events, then analyze causes.
- Decide corrective actions, assign owners and dates, and write the report.
- Follow up to confirm actions were completed and actually worked.
Finding root causes
The immediate cause is the act or condition right before the event: a guard was off, a ladder slipped. Root causes are the underlying reasons that allowed it: the guard has to come off for cleaning and there is no lockout procedure for that task; ladders are used because the scaffold takes too long to book.
Common methods include:
- Five whys. Keep asking why until you reach something the organization can change. Simple and useful for smaller events.
- Cause and effect (fishbone) diagrams. Sort contributing factors into categories such as people, equipment, materials, methods, environment and management.
- Timeline and barrier analysis. Map what controls should have stopped the event and why each one failed or was missing.
"Worker did not follow procedure" is rarely the end. Ask why. Was the procedure known, practical, enforced, and suited to the job? Was the worker rushed, tired, or short of the right tool? Stopping at blame guarantees a repeat.
Writing good corrective actions
Each corrective action should tie to a cause you found, sit as high as possible on the hierarchy of controls, and be specific enough that anyone can tell whether it was done.
| Weak action | Stronger action |
|---|---|
| Remind workers to be careful | Install a fixed guardrail at the mezzanine edge by the end of the month |
| Retrain the worker | Revise the cleaning procedure to include lockout steps, train all three shifts and verify through observation |
| Review the procedure | Rewrite the procedure with the crew who do the work, then trial it for two weeks |
The report
A clear report includes a description of what happened, the sequence of events, immediate and root causes, corrective actions with owners and dates, and the names of the investigation team. Share the lessons with crews who do similar work. Keep the report with your records, and give the committee or representative access as your province requires.
How ehZee can help
ehZee helps employers set up incident reporting and investigation procedures, train investigation teams and review past investigations for patterns. See safety program development and review.
Common questions
Who should lead an investigation?
Someone trained in investigation methods, with enough authority to get access to people and records, and enough independence to report honestly. Including a worker representative improves both the findings and the trust in them.
Should every first aid case be investigated?
Every one should be recorded. The depth of investigation can be scaled to potential severity, but patterns across minor injuries often point to bigger risks.
Can the investigation be used to discipline someone?
Mixing investigation with discipline makes people stop talking, which makes future investigations less useful. If discipline is considered, keep it as a separate process.