Incident investigations, including a thorough root cause analysis, should be happening after any injury, property damage event, or near miss happens on the job. Following the investigation, appropriate corrective actions can be implemented to prevent future incidents.
The term accident often used when referring to an unplanned, unwanted event. However, accident suggests an event that was random, and could not have been prevented. Since nearly all worksite fatalities, injuries, and illnesses are preventable, the term incident is more applicable in most of these unfortunate situations.
Investigating a worksite incident, which may be a fatality, an injury, an illness, property damage, or a close call, provides employers and workers the opportunity to identify hazards in their operations and shortcomings in their safety and health programs. Most importantly, it enables employers and workers to identify and implement the corrective and preventative actions necessary to prevent future incidents.
Incident investigations that focus on identifying and correcting root causes, not on finding fault or blame, also improve workplace morale and increase productivity, by demonstrating an employer's commitment to a safe and healthful workplace.
Incident investigations are often conducted by a supervisor, but to be most effective, these investigations should include managers and employees working together, since each bring different knowledge, understanding, and perspectives to the investigation.
In conducting an incident investigation, the team must look beyond the immediate causes of an incident. It is far too easy, and often misleading, to conclude that carelessness or failure to follow a procedure was the main cause of an incident. When the incident investigation fails to uncover the root cause(s) of the incident then the organization will fail to identify the systemic changes and measures that are needed to prevent future incidents.
Remember – before an incident investigation begins, all emergency response actions need to be completed and the incident site must be safe and secure for entry and investigation.
OSHA recommends a four-step systems approach to incident investigations.
Step 1 – Preserve and Document the Scene
Preserve the integrity of incident location and prevent material evidence from being removed or altered. Use cones, tape, or other means of guarding to prevent unauthorized entry.
Step 2 – Collect Information
Information about what happened before and during the incident can be collected through visual observation of the location, interviews, and document review efforts.
Step 3 – Determine Root Causes
There is often more than one root cause that can be uncovered during any incident investigation, and finding these root causes requires a deep evaluation of the incident.
Step 4 – Implement Corrective and Preventative Actions
Steps taken after an incident to prevent future similar incidents, should be implemented in such a way that specifically addresses the root cause(s) found during the investigation.
When a program weakness is identified during an incident investigation, it is important to ask why it existed and why it was not previously addressed.
- If a step in the standard operating procedure was skipped, why was the procedure not followed exactly?
- Did production pressures play a role, and, if so, why were production pressures permitted to jeopardize safety?
- Was the procedure out-of-date or safety training inadequate? If so, why had the problem not been previously identified, or, if it had been identified, why had it not been addressed?
These examples illustrate that it is essential to discover and correct all the factors contributing to an incident, which nearly always involve equipment, procedural, training, and some other safety program deficiency. Simply placing blame on the employee, indicating that they made a mistake, or failed to follow the procedure, is not acceptable during an incident investigation.
A successful root cause analysis identifies all root causes—there are often more than one.
For simpler incidents, brainstorming and checklists may be sufficient to identify the root cause(s). For more complicated incidents, logic/event trees should also be considered. Timelines, sequence diagrams, and causal factor identification can also be useful tools.
Regardless of the tools used, the investigation should be seeking to answer these four important questions:
- What happened?
- How did it happen?
- Why did it happen?
- What needs to be corrected so it doesn’t happen again?
Addressing underlying or root causes is necessary to truly understand why an incident occurred, to develop truly effective corrective and preventative actions, and to minimize or eliminate serious consequences from similar future incidents.
To assist employers and workers in conducting effective incident investigations, and to develop corrective action plans, the following resources can help:
OSHA Fact Sheet: The Importance of Root Cause Analysis During Incident Investigation
OSHA Incident Investigations: A Guide for Employers
NSC How to Conduct an Incident Investigation
Washington State Department of Labor & Industries Accident Investigation Basics PowerPoint Presentation