Accident Investigation


Accident prevention and control of hazards is the result of a well designed and executed safety and health program. One of the keys to a successful program includes unbiased, prompt and accurate accident investigations. The basic purpose of these investigations is to determine measures that can be taken to prevent similar accidents in the future. This chapter addresses:

  • Company Policy
  • Responsibilities
  • Hazard Control
  • Role of Supervisors
  • Investigation Procedures


It is the policy of [COMPANY] that investigation of all work related accidents, injuries and illnesses are to be conducted in a professional manner to identify probable causes and are used to develop specific management actions for the prevention of future accidents.



  • Conduct accident prevention and investigation training for supervisors
  • Ensure all accidents and injuries are properly investigated
  • Ensure immediate and long term corrective actions are taken to prevent reoccurrence
  • Maintain Accident Reports permanently on file
  • Ensure proper entries are made on the OSHA 200 Log and First Report of Injury
  • Provide all necessary medical care for injured workers


  • Conduct immediate initial accident investigations
  • Report all accidents to management as soon after the event as possible
  • Collect and preserve all evidence that may be useful in an investigation
  • Conduct interviews of witnesses in a polite professional manner
  • Do not attempt to find or assign blame for accidents
  • Take action to protect people and property from secondary effects of accidents


  • Immediately report all accidents & injuries to their supervisor
  • Assist as requested in all accident investigations
  • Report all hazardous conditions and near-misses to supervisors

Hazard Control

Engineering Controls – There are numerous engineered safeguards throughout the facility used to protect employees and prevent exposure to hazards. Examples of engineering controls are machine guards, safety controls, isolation of hazardous areas, monitoring devices, etc. Specific engineering controls are addressed in other chapters of the company safety manual and in equipment and process procedures.

Administrative Controls – These controls involve the use of procedures, assessments, inspection, records to monitor and ensure safe practices and environments are maintained. Other administrative controls are in place to identify new hazards and implement corrective action. Examples of administrative controls are periodic inspections, equipment operating and maintenance procedures, hazard analysis, selection and assignment of personal protective equipment, etc.

Training Controls – This aspect of hazard control is used to ensure employees are fully and adequately trained to safely perform all tasks to which they are assigned. No employee is to attempt any task without proper training in the equipment used, required personal protective equipment, specific hazards and their control and emergency procedures. Examples of training controls are initial new hire safety orientation, job specific safety training and periodic refresher training.

Supervisor Involvement

In most cases, the immediate area supervisor will conduct the initial phase of an accident investigation. This initial activity is primarily a recording of facts involved in the accident, list of affected employees and witnesses. Direct supervisors are familiar with employee’s work environment & assigned tasks. Supervisors must take the accident situation under control and immediately eliminate or control hazards to others.

Immediate Steps

1. Provide First Aid for any injured persons.

2. Eliminate or control hazards

3. Document accident scene information to determine the cause.

4. Interview witnesses immediately.

Accident Prevention

Accidents are usually complex. An accident may have 10 or more events that can be causes. A detailed analysis of an accident will normally reveal three cause levels: basic, indirect, and direct. At the lowest level, an accident results only when a person or object receives an amount of energy or hazardous material that cannot be absorbed safely. This energy or hazardous material is the DIRECT CAUSE of the accident. The direct cause is usually the result of one or more unsafe acts or unsafe conditions, or both. Unsafe acts and conditions are the INDIRECT CAUSES or symptoms. In turn, indirect causes are usually traceable to poor management policies and decisions, or to personal or environmental factors. These are the BASIC CAUSES.

Most accidents are preventable by eliminating one or more causes. Accident investigations determine not only what happened, but also how and why. The information gained from these investigations can prevent recurrence of similar or perhaps more disastrous accidents. Accident investigators are interested in each event as well as in the sequence of events that led to an accident. The accident type is also important to the investigator. The recurrence of accidents of a particular type or those with common causes shows areas needing special accident prevention emphasis.

Initial Investigation Procedures

The initial investigation has three purposes:

1. Prevent further possible injury and property damage

2. Collect facts about the accident

3. Collect and preserve evidence


a. Secure the area. Do not disturb the scene unless a hazard exists.

b. Prepare the necessary sketches and photographs. Label each carefully and keep accurate records.

c. Interview each victim and witness. Also interview those who were present before the accident and those who arrived at the site shortly after the accident. Keep accurate records of each interview. Use a tape recorder if desired and if approved.


a. What was not normal before the accident.

b. Where the abnormality occurred.

c. When it was first noted.

d. How it occurred.

Follow-up Accident Investigation

The follow-up investigation is used to analyze data and determine the causes and corrective actions necessary to prevent reoccurrence.


a. Analyze the data obtained in the initial investigation

b. Repeat any of the prior steps, if necessary.

c. Determine

1. Why the accident occurred.

2. A likely sequence of events and probable causes (direct, indirect, basic).

d.. Determine the most likely causes.

e.. Conduct a post-investigation briefing.

f.. Prepare a summary report, including the recommended actions to prevent a recurrence.

An investigation is not complete until all data are analyzed and a final report is completed. In practice, the investigative work, data analysis, and report preparation proceed simultaneously over much of the time spent on the investigation.

Conducting Interviews

In general, experienced personnel should conduct interviews. All interviews should be conducted in a quite and private location. It is essential to get preliminary statements as soon as possible from all witnesses. Investigators should not provide any facts to the witness – only ask non-leading questions.

a. Explain the purpose of the investigation (accident prevention) and put each witness at ease.

b. Listen, let each witness speak freely, and be professional, courteous and considerate.

c. Take notes without distracting the witness. Use a tape recorder only with consent of the witness.

d. Use sketches and diagrams to help the witness.

e. Emphasize areas of direct observation. Label hearsay accordingly.

f.. Do not argue with the witness.

g. Record the exact words used by the witness to describe each observation.

h.. Identify each witness (name, address, occupation, years of experience, etc.).

Accident Analysis

Accidents represent problems that must be solved through investigations. Formal procedures are helpful in identifying and solving problems. This section discusses two of the most common procedures: Change Analysis and Job Safety Analysis.

Change Analysis

As its name implies, this technique emphasizes change. To solve a problem, an investigator must look for deviations from the norm. Consider all problems to result from some unanticipated change. Make an analysis of the change to determine its causes. Use the following steps in this method:

1. Define the problem (What happened?).

2. Establish the norm (What should have happened?).

3. Identify, locate, and describe the change (What, where, when, to what extent).

4. Specify what was and what was not affected.

5. Identify the distinctive features of the change.

6. List the possible causes.

7. Select the most likely causes.

Job Safety Analysis

Job safety analysis (JSA) is part of many existing accident prevention programs. In general, JSA breaks a job into basic steps, and identifies the hazards associated with each step. The JSA also prescribes controls for each hazard. A JSA is a chart listing these steps, hazards, and controls. Review the JSA during the investigation if a JSA has been conducted for the job involved in an accident. Perform a JSA if one is not available. Perform a JSA as a part of the investigation to determine the events and conditions that led to the accident.

Investigation Report

An accident investigation is not complete until a report is prepared and submitted to management. To be and effective tool, an accident report should be clear and concise. The purpose of the investigation is to prevent future accidents. The following outline has been found especially useful in developing the information to be included in the formal report:

1. Background Information

a. Where and when the accident occurred

b. Who and what were involved

c. Operating personnel and other witnesses

2. Account of the Accident (What happened?)

a. Sequence of events

b. Extent of damage

c. Accident type

d. Agency or source (of energy or hazardous material)

3. Discussion (Analysis of the Accident – HOW; WHY)

a. Direct causes (energy sources; hazardous materials)

b. Indirect causes (unsafe acts and conditions)

c. Basic causes (management policies; personal or environmental factors)

4. Recommendations (to prevent a recurrence) for immediate and long-range action to remedy:

a. Basic causes

b. Indirect causes

c. Direct causes (such as reduced quantities or protective equipment or structures)

Possible Causes

Obvious accident causes are most probably symptoms of a “root cause” problem. Some examples of Unsafe Acts and Unsafe Conditions which may lead to accidents are:

Unsafe Acts

Unauthorized operation of equipment

Running – Horse Play Not following procedures By-passing safety devices

Not using protective equipment

Under influence of drugs or alcohol

Unsafe Conditions

Ergonomic Hazards

Environmental hazards

Inadequate housekeeping

Blocked walkways

Improper or damaged PPE

Inadequate machine guarding


As a result of the finding is there a need to make changes to:

Employee training

Work Stations Design

Policies or procedures


All accident reports will be maintained on file permanently. They shall receive timely review by upper management to ensure proper corrective actions have been taken.

First Report of Injury (OSHA 101 form) and OSHA 200 Log entries will be made within 8 hours of notification of injuries or illnesses.