Knowing how to properly conduct a root cause analysis is imperative when handling a safety incident investigation.
It isn’t just OSHA that encourages the use of root cause during an incident investigation, but also the EPA under their Risk Management Program(RMP).
Concerning Root Cause Analysis OSHA says:
During an incident investigation, an employer must determine which factors contributed to the incident, and both OSHA and the EPA encourage employers to go beyond the minimum investigation required and conduct a root cause analysis. A root cause analysis allows an employer to discover the underlying or systemic, rather than the generalized or immediate, causes of an incident. Correcting only an immediate cause may eliminate a symptom of a problem, but not the problem itself. – Source
a) Each employer —
(1) shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees;
The 5 Why Method as a Root Cause Analysis Method for Workplace Incidents
The 5 Whys technique can also be used as a method for determining root causes of workplace incidents. What would 5 Whys look like in the context of a workplace incident investigation? Here’s the application of 5 Whys to an example mentioned in an OSHA fact sheet:
The Problem: A worker slips and falls, and suffers an injury.
1st Why: There was a puddle of oil on the plant floor.
2nd Why: Oil spilled from a compressor.
3rd Why: An oil leak from the compressor was not detected.
4th Why: The compressor was not inspected on a regular basis and repaired (if required).
5th Why and the Root Cause: The compressor was not in the maintenance system.
In theory it takes five “whys” to get to the root cause, but in practice there will be cases where you may use more or fewer than five “whys”.
Finally, according to the Washington State Department of Labor & Industries, these are the benefits of asking the 5 Whys:
- Simplicity: Easy to use and requires no advanced mathematics or tools.
- Effectiveness: Helps to quickly separate symptoms from causes and identify the root cause.
- Comprehensiveness: Helps to determine relationships between various problem causes.
- Flexibility: Works well alone and when combined with other methods.
- Engaging: Fosters teamwork.
- Inexpensive: A guided, team-focused exercise with no additional costs.
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