Why Conduct An Accident Investigation?

It’s critical to learn from the past and prevent accidents from occurring in the future.

By Gary Ganson, CSP, CIH

The first priority after an accident occurs is—of course— the safety of the employees involved. Once the severity of the accident has been properly managed, a quick and in-depth investigation should be conducted as soon as possible.

To help understand terms used in this column, the term “accident” can be defined as an unplanned event that disturbs the completion of an activity that may or may not include injury or property damage. An accident typically refers to an unexpected event that didn’t cause injury or damage, but had the potential.

When accidents are investigated, emphasis should be on finding the root cause of the accident, rather than the investigation procedure itself, so you can prevent it from happening again. The purpose is to identify facts that can lead to corrective actions—not to find fault. In conducting the investigation, look for single or multiple causes that contributed to why the accident happened.

What are the reasons to investigate a workplace accident?

  • To find out the root cause of the accident
  • To prevent a similar accident reoccurring
  • To fulfill any regulatory requirements
  • To determine the cost and losses caused by the accident
  • To process workers’ compensation claims.

If you are the one leading an accident investigation, include all incidents involving no personal injury or property damage to determine the hazards that should be corrected or managed. The same principles apply to a quick inquiry of a minor accident as they do to the more formal investigation of a serious accident.

Who should participate in the accident investigation?

The best investigations are conducted by applying a team approach. The person leading the team should be someone experienced in accident causes and investigative techniques. Each team member should have some knowledge of the work processes, procedures, people involved, and the environment of a particular situation. If your employees are represented by a labor union, including hourly employees or union management on the team is highly recommended and probably is required under the labor contract.

Here is an example of team members to include on the accident investigation:

  • Employees with knowledge of the work being done
  • Supervisor of the employees involved in the accident
  • Senior or corporate management
  • Safety and health manager
  • Health and safety committee if one exists
  • Union representative, if applicable
  • Employees with experience in investigations
  • Witnesses to the accident.

What to look for as the root cause

There are a number of things that contribute to an accident. Was it caused by unsafe conditions? Was it caused by unsafe actions by the employee? Don’t focus on only one or the other as the single event that caused the accident. Look at the conditions surrounding the accident and what actions or human errors occurred. The team must uncover all the underlying facts in the chain of events that led up to the accident.

One of the most important points to remember in the investigation: Even when it appears obvious to the investigating team there is a single cause, this should not indicate the end of determining the root cause.

Rarely is there a single cause. For example, consider an employee pushing the wrong button on a crane and dropping the load, causing personal injury. Was the employee not paying attention? Was there a distraction? Was he not properly trained? These are just a few of the questions to consider.

Others might include:

  • If the employee was distracted, why or what was the distraction?
  • Was a safe work procedure being followed? If not, why not?
  • Were safety devices in order? If not, why not?
  • If the employee was not properly trained, why not?

Steps involved in investigating an accident

The accident investigation must start as quickly as possible.

Here are some simple steps to follow:

  • Preserve conditions as much as possible at the scene after all personnel have been treated, removed, and the location stabilized, preventing any further risk for injury.
  • Talk with witnesses and obtain their testimony of the facts they observed.
  • Assemble the team to discuss the observed conditions, the facts of the accident, and the testimony of witnesses in order to identify the causes.
  • Complete a report of the results from the investigation.
  • Develop a strategy and institute a plan for corrective action.
  • Conduct a later follow-up to evaluate the effectiveness of the corrective plan.

All of the strategy to put change into action should happen as quickly as possible to prevent complacency setting in.

What to look for as the cause of an accident

While there are many accident investigation models, here are just a few tips to use during the investigation to evaluate what may have caused the accident.

What was the task being performed at the time of the accident?

The accident investigation team will need to look for the answers to questions such as:

  • Was there a written and trained procedure used?
  • Were the appropriate tools and materials available and used?
  • Had workplace conditions changed to make the procedure unsafe?
  • Were safety devices in place and working properly?
  • Were there any defects in equipment?
  • Were employees trained and familiar with equipment and processes? The team then asks itself: “If not, why not?”

Material used in the process

  • Was there an equipment failure, and if so, what caused it to fail?
  • Was the machinery poorly designed or maintained?
  • Were hazardous materials involved?
  • Were hazardous materials identified and employees aware of them?
  • Was the raw product defective in some way?
  • Was PPE available, used, and employees trained in its use? Same concern: “If not, why not?”


What were the conditions at the time of the accident and could they have contributed?

  • What were the weather conditions?
  • Was poor housekeeping a problem?
  • Was it too hot or too cold?
  • Was noise a problem?
  • Was there adequate light?
  • Were there physical distractions from outside sources?
  • Were any toxic or hazardous gases, dusts, or fumes present?


Here are some ideas to evaluate during the investigation— but with the purpose of finding out the factual causes, not to place blame.

  • Were workers trained and experienced in the work they were doing?
  • Were they physically able to do the work?
  • What was the status of their health?
  • Were they tired?
  • Were they under stress (work or personal)?


Management has a legal responsibility for the safety of the workplace. As such, the role of supervisors and management must always be considered in an accident investigation.

  • Were safety rules communicated to and understood by all employees?
  • Were written procedures and training orientation provided?
  • Were they being enforced?
  • Was there adequate supervision?
  • Had hazards been previously identified?
  • Was PPE provided and employees trained in its use?
  • Were unsafe conditions corrected?
  • Was regular maintenance of equipment carried out?
  • Were regular safety inspections carried out?

The steps in accident investigation are quite simple. The accident investigators gather information, analyze information, draw conclusions, and make recommendations.

The procedures are straightforward, but each step can have its pitfalls. Keeping an open mind is necessary in accident investigation— preconceived notions may result in some wrong paths being followed while leaving some significant facts uncovered. All possible causes should be considered. Making notes of ideas as they occur is a good practice, but no conclusions should be drawn until all the information is gathered.

As the team wraps up the accident investigation, here are some pointers in preparing the conclusion and writing up the report.

  • Keep an open mind in evaluating the step-by-step account of the accident details.
  • Focus on the factual details that are objective to what happened. Avoid assumptions in the investigative phase.
  • When making recommendations, be factual, specific, and identify corrective actions for root causes to eliminate contributing factors. Include identified unsafe actions and unsafe conditions.
  • Develop a timetable and schedule of corrective actions with follow-up checks to verify completion.
  • Involve all affected employees in the corrective actions. Their knowing what happened, why, and how will help prevent future problems.

While no company wants accidents to occur, learning from what did happen in the past is a good way to make sure it doesn’t happen again.

To help meet your professional needs, this column covers skills and competencies found in DACUM charts for drillers and pump installers. DO refers to the drilling chart and PI represents the pumps chart. The letter and number immediately following is the skill on the chart covered by the column. This column covers:

DOC-6, 9; DOD-4, 5; DOK-2, 9; DOL-1, 2, 3, 4; PIB-1, 2, 8; PIE-2, PIG-3

More information on DACUM and the charts are available at www.NGWA.org.

Gary Ganson, CSP, CIH, a certified industrial hygienist and certified safety professional, is a senior consultant for Terracon in Lenexa, Kansas.