Incident Investigation & Root Cause
The goal of an incident investigation is to keep it from happening again, not to find someone to blame. “Worker wasn’t careful” is almost never the real cause. Good investigations dig into why the hazard existed and why the system let it reach a person.
- Supervisors
- Safety Committees
What to investigate
- Injuries and illnesses, including first aid cases
- Near misses, which are free lessons
- Property and equipment damage, utility strikes, vehicle incidents
- Spills and releases
Steps
- Care and control: get medical care for the injured, and make the area safe.
- Preserve the scene: don’t move equipment or materials unless needed for safety; take photos and measurements.
- Gather facts: what happened, step by step, with times. Collect documents: permits, JHAs, training records, inspection logs.
- Interview the injured worker (when able), witnesses and others familiar with the task, separately and soon. Ask open questions.
- Find root causes: ask “why” until you reach things management can fix.
- Choose corrective actions using the hierarchy of controls. See Hierarchy of Controls.
- Assign, track and verify that each fix is done and working.
- Share the lessons with crews and other sites.
The 5 Whys (example)
| What happened | A worker cut a hand with a utility knife |
|---|---|
| Why? | The blade slipped while cutting thick plastic strapping |
| Why? | The blade was dull, and the worker was pulling toward the other hand |
| Why? | No spare blades on site, and no strap cutters provided |
| Why? | Nobody was assigned to stock tools for this task |
| Fix | Provide strap cutters and self-retracting knives, stock blades, add it to the JHA, and assign responsibility |
Look beyond the worker
- Equipment, tools and PPE: right ones, working, available?
- Procedures: clear, realistic, followed?
- Training: did the person know how and why?
- Planning and supervision: was the task planned and hazards identified?
- Pressures: schedule, staffing, fatigue, weather?
Blame drives reporting underground. If workers expect punishment, near misses stop being reported. Retaliating against someone for reporting an injury is illegal. See Whistleblower Protection.
Standards & references
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