OSHA's incident investigation guidance emphasizes finding root causes rather than assigning blame. Investigations focused on "who" usually stop at human error. Investigations focused on "why" find the conditions that will cause the next event.
1. Secure and preserve
Make the scene safe, provide care, and preserve evidence: photos, equipment, documents and the scene itself where possible.
2. Gather facts
- Interview witnesses separately and promptly
- Collect the procedures, training records, permits and inspection history involved
- Build a timeline from before the event to the response
3. Identify contributing factors
Consider people, equipment, materials, environment, procedures and management systems. Most incidents have several.
4. Determine root causes
Keep asking why until you reach a cause that management can control — a missing procedure, an inadequate inspection frequency, an unclear responsibility.
5. Assign corrective actions
Each root cause should produce at least one action with an owner, due date and verification method. Favor controls higher in the hierarchy: elimination, substitution and engineering controls before administrative controls and PPE.
6. Share what you learned
Revise documents, update training and communicate lessons to the employees doing similar work — and confirm they received it.
