How to Conduct an Incident Investigation Using the 5 Whys Method

When a workplace incident occurs — whether it’s a near miss, injury or property damage — it’s critical to dig deeper than surface-level explanations. At OECS, we guide organizations through thorough incident investigations to uncover the true root cause, not just the symptoms. One of the most effective tools in our approach is the 5 Whys method.

What Is the 5 Whys Method?

The 5 Whys is a problem-solving technique that helps identify the root cause of an issue by asking “Why?” five times (or as many times as needed). It’s simple, but powerful and it prevents quick-fix solutions that don’t address the real problem.

Why Use the 5 Whys for Incident Investigations?

Workplace incidents are rarely caused by a single factor. A broken ladder may seem like the issue, but the real cause could be a lack of preventive maintenance, poor training or even an unclear safety policy. The 5 Whys exposes these underlying issues, allowing organizations to:

• Prevent repeat incidents
• Strengthen safety procedures
• Improve compliance with OSHA standards
• Foster a proactive safety culture

How to Conduct an Incident Investigation with the 5 Whys

At OECS, we recommend integrating the 5 Whys into your incident investigation process as follows:

1. Gather the Facts

Document what happened, who was involved, when and where the incident occurred and what conditions were present. Use photos, witness statements and any available records.

2. Assemble the Right Team

Include individuals with firsthand knowledge of the incident and a strong understanding of operations and safety. A team approach leads to better insights and reduces bias.

3. Ask “Why?”—and Keep Going

Start with the immediate cause and ask why it happened. Then ask why that happened. Continue until you uncover the root cause.

Example:

• Problem: A worker slipped on a wet floor.
• Why 1: The floor was wet.
• Why 2: A pipe was leaking.
• Why 3: The pipe hadn’t been inspected in months.
• Why 4: There’s no regular maintenance schedule.
• Why 5: Our safety program doesn’t include preventive maintenance policies.

The real issue wasn’t just a wet floor, it was a gap in the safety program. Now you know what to fix.

4. Identify Corrective Actions

Once the root cause is clear, develop corrective and preventive actions that address it directly. These may include policy changes, training updates or equipment maintenance schedules.

5. Follow Up and Document

Track the implementation of corrective actions and ensure they’re effective. Document everything. A thorough report not only satisfies OSHA requirements — it protects your business and your people.

Partner with OECS for Expert-Led Incident Investigations

Whether you’re responding to a serious injury or a close call, OECS can guide your team through a comprehensive, objective incident investigation process. We bring decades of experience in root cause analysis, OSHA compliance and safety culture building.

Ready to strengthen your safety program? Contact OECS today to schedule a consultation or learn more about our incident investigation training.