The construction environment presents many potential hazards that can result in serious injuries to workers and other incidents such as property or equipment damage. After an incident occurs, everyone is usually concerned with “what happened,” which is often fairly clear cut and easy to identify. However, “why it happened” can be much more challenging to answer.

Conscientious contractors perform incident investigations immediately after all incidents, even near misses (close calls). It’s important that these investigations are prompt and thorough because an incomplete, inaccurate or biased investigation can exacerbate the problem and increase potential liability.

LIUNA General Secretary-Treasurer and LHSFNA Labor Co-Chairman Armand E. Sabitoni

The most essential aspect of a comprehensive incident investigation is identifying the root cause. A root cause is the fundamental, underlying reason why an incident occurred. There is always a chain of events or “error chain,” that led to the incident. Every link in the chain needs to be carefully investigated through a root cause analysis to identify the correctable system failure(s) that led to the incident.

“The point of incident investigations isn’t to assess blame. The goal is to prevent the incident from happening again to improve the safety of all workers on site and keep the project running smoothly,” says LIUNA General Secretary-Treasurer and LHSFNA Labor Co-Chairman Armand E. Sabitoni. “Without a root cause analysis, it’s difficult to get to the critical point of understanding why the incident occurred and taking the steps to prevent it from happening again in the future.”

Both OSHA and the Environmental Protection Agency (EPA) urge employers, including owners, contractors and operators, to conduct a root cause analysis following any incidents or near misses.

Benefits of Performing a Root Cost Analysis

The primary goal of conducting a root cause analysis is to prevent similar events from happening again. This helps reduce the risk of death or injury to workers and the public and also lowers the chances for damage to property or the environment. There are several other benefits employers should consider:

• Avoiding unnecessary costs resulting from business interruptions, emergency response and clean-up, increased regulation, audits, inspections and OSHA or EPA fines. Regulatory fines can be costly, but litigation costs can often substantially exceed these fines.
• Employers may find they are spending money to fix the results of incidents that could have been prevented (or reduced in severity or frequency) by correcting the underlying cause or system failure.

• Employers who focus on incident prevention build trust with workers and the public. Employers with a positive record are also more likely to attract and retain high-performing staff.
• A robust process safety program that includes root cause analysis can lead to more effective control of hazards, improved process reliability, increased revenues, decreased production costs, lower maintenance costs and lower insurance premiums.

If all contributing factors are not identified and action plans are not implemented to address each factor, the risk for a similar incident to occur will continue to exist.

Effective Tools for Root Cause Analysis

There are many different tools that can be used to conduct a successful root cause analysis. Ideally, a combination of these tools should be used:

• Brainstorming
• Checklists
• Logic/Event Trees
• Timelines
• Sequence Diagrams
• Causal Factor Determination

For simpler incidents, brainstorming and checklists may be sufficient to identify root causes. For more complicated incidents, logic/event trees should also be considered. Timelines, sequence diagrams and causal factor identification are often used to support the logic/event tree tool. Regardless of the combination of tools chosen, employers should use these tools to answer four important questions:

• What happened?
• How did it happen?
• Why did it happen? (This may need to be asked multiple times.)
• What needs to be corrected?

Interviews and review of documents, such as maintenance logs, can be used to help answer these questions. Involving employees in the root cause investigation process and sharing the results will go a long way toward preventing similar incidents in the future.

OSHA’s Incident Investigation page and guide for employers both include more information on how to conduct a successful root cause analysis. The National Safety Council also developed a helpful guide and the Washington State Department of Labor & Industries created an online course about what to look for during an investigation. For more help, contact the LHSFNA’s Occupational Safety & Health Division.

[Travis Parsons is the OSH Division’s Senior Safety & Health Specialist.]