Article

Workplace accident investigation

Workplace accident investigations are designed to identify the root cause of workplace accidents to help prevent future accidents. Effective reporting should follow a standard format and may require the involvement of several people, depending on the severity of the accident/incident. The investigation team should be trained on how to conduct investigations, and complete and analyze accident investigation reports.

Reasons for investigating accidents

Accidents may be an indication that the safety program, workplace communication, training, supervision or work procedures are deficient. By finding the root cause, or multiple causes, of an accident, necessary improvements can be identified and made in the organization. Investigations are not designed to blame an employee and it is essential that all workers understand this. Accidents typically have multiple root causes and only by investigation of the circumstances will these causes be identified for corrective action.

Examples of accidents that may need investigation include:

  • Injury, illness, or property damage —This includes when employees, contractors, and the general public are involved.
  • “Near misses” (cases when no injury, illness, or property damage occurred, but if conditions were slightly changed damage would be probable)

Investigation policy

While it is recommended that all accidents are investigated, regardless how minor, it is important that the company decide when and what types of accidents will be investigated. The policy should require accident investigations to begin as soon as possible to minimize forgetfulness, changing conditions and other factors that could prevent identifying the root cause.

Key principles of accident investigation that should be a part of every policy:

  • Primary or underlying cause (root cause) of the accident and its contributing causes are discovered
  • Taking corrective action for every accident cause that is discovered in order to prevent recurrence. Assign a person to be responsible and a completion date to each corrective action. Assign someone from management to follow-up on corrective actions to ensure that each action is accomplished on time.
  • Communicating accident findings to all employees when completed, along with program changes that result from corrective actions
  • Determining if training or retraining is necessary to prevent future occurrences

Those conducting the investigations should be trained in investigation procedures, securing and protecting evidence, gathering facts and interviewing witnesses. An investigator must avoid assigning blame. To blame someone would be counterproductive to the investigation and might hinder future investigations.

Accident investigations should be conducted as soon as possible after the incident. When injuries are involved, the investigation usually begins after medical assistance has been provided and the injured employee has been transported to a medical facility. However, if an investigation can be started without obstructing medical assistance, then it should begin immediately.

Investigation steps

There are nine steps that add up to a thorough and effective investigation.

  1. Preparing for the investigation
  2. Gathering the facts about the accident
  3. Analyzing the data
  4. Developing unbiased conclusions
  5. Analyzing conclusions based only on the facts
  6. Developing the report
  7. Developing recommendations
  8. Following through on recommendations
  9. Following up on corrective actions

Preparing for the investigation

Preparation before an accident occurs will ensure the investigation can be carried out properly and important facts can be gathered. Trying to create an investigation process post-accident will usually result in missed information and fact finding opportunities.

A plan or procedure that includes training supervisors on how to conduct a thorough accident investigation should be in place before the accident occurs.

Gathering the facts

While preparation and training should be completed well in advance of any actual accidents, the gathering of facts begins only when an accident/incident has actually taken place. Document the facts with photographic evidence, measurements and records (current written work procedures, training records, workplace/equipment inspections, delivery logs, etc.). Don’t focus solely on physical evidence, but be inquisitive about communications between supervisors and employees and whether training was provided and adequate. Remember that the facts will have to hold up over time and through fading memories of witnesses. If it is important, document it.

Analyzing the data

This is an ongoing process that begins when you start to gather the facts and consider how they may have contributed to the accident’s cause. Witness statements should be compared to where they were located when the accident occurred.

  • Did they have firsthand visual sight of the accident or did they hear something?
  • Do their statements appear to be in line with the other evidence?
  • Do the facts indicate that procedures were not followed or properly communicated?
  • Do the facts point to improper or deficient training of workers?

As the facts are analyzed, other questions may arise and additional investigation may be necessary to get the full picture.

Developing conclusions

As the facts are gathered and analyzed, conclusions can begin to be drawn about what happened and what caused the accident to happen. Conclusions should be based only on verifiable facts, not opinion. Writing down conclusions based on all contributing facts will help to identify any missing gaps and may point to areas where additional information is necessary. If the facts don’t add up, you may not have all the information and more fact-gathering and analysis may be necessary. When developing conclusions, you should think about how, what, why, when and where, to understand whether you have a fact for each question.

Analyzing the conclusions

As time was taken to formally develop tentative conclusions, it is just as important to take the time to examine and analyze those conclusions. This, too, may send you back to earlier steps to gather more facts or to review from a different standpoint. Eventually, tentative conclusions can either be made firm or discarded altogether.

Making the report

The accident report brings all information together: facts, analysis, and conclusions.

  • The information has been gathered on the people involved, the situation or specific incident.
  • The facts have been reviewed and analyzed.

Everything included in the report should be supported by facts and evidence; unsubstantiated statements or mere speculations do not belong in the final report.

The report narrative should begin with a short synopsis, including one or two lines that state what happened without details or causes. This should be followed by a detailed and more complete account of the accident. (In selecting detail, however, stick to essentials, leaving out extraneous information that does not lead to an understanding of the incident or conclusions.)

A good report should be clear and concise, and not a running narrative that includes information that is not relevant to the accident cause. Consider that the person reading the report may not be familiar with the facility, work tasks or the process involved but must understand how and why the accident occurred.

Making recommendations

The main goal of any accident investigation is to determine what corrective action needs to be taken to prevent any future occurrences. Recommendations on corrective action should clearly state what should be done to correct the situation. There may be several corrective actions and each should be listed and include who is responsible to implement the action and when the action will be completed.

Follow up

Once the report is completed it is important to ensure the corrective actions have been implemented. Supervisors who have been assigned to a corrective action may not understand how to effectively implement the action or may not implement it effectively. Someone should be assigned to ensure the action taken matches the action recommended and that all recommendations have been implemented.


This material is provided for informational purposes only and does not provide any coverage or guarantee loss prevention. The examples in this material are provided as hypothetical and for illustration purposes only. The Hanover Insurance Company and its affiliates and subsidiaries (“The Hanover”) specifically disclaim any warranty or representation that acceptance of any recommendations contained herein will make any premises, or operation safe or in compliance with any law or regulation. By providing this information to you. The Hanover does not assume (and specifically disclaims) any duty, undertaking or responsibility to you. The decision to accept or implement any recommendation(s) or advice contained in this material must be made by you.

LC DEC 2018 12-169
171-0829 (12/18)