Types of accident investigations
When to investigate
What to investigate
Who should investigate
Conducting the investigation
Interviewing the witness
Ten accident investigation mistakes to avoid
Rationale for investigating
• The primary reason for investigating
accidents is not to identify a scapegoat,
but to determine the cause of the
• This information benefits the ongoing
effort of reducing the likelihood of
accidents, and preventing similar
accidents from happening in the future.
When should an investigation be
• According to OSHA document 2056 employers
of 11 or more employees must maintain records
of occupational injuries and illnesses as they
• If an accident results in the death of an
employee or hospitalization of 5 or more
employees, a report must be submitted to the
nearest OSHA office within 48 hours. This rule
applies regardless of the size of the company.
• The saddest part of non reporting of accidents is
that they are not investigated to determine and
eliminate the cause.
Accident report and accident
An accident report is completed when the accident in question
represents only a minor incident. It answers the following questions:
who, what, where, and when. However it does not answer the why
question. Supervisors often complete accident reports. OSHA form
301 can be used for accident reports.
An accident analysis report is completed when the accident in
question is serious. It answers all the questions: who, what, where,
when, and why. Accident analysis must identify the actual root
cause or the company will expend resources treating only the
symptom or even worse solving the wrong problem. Serious
accidents are always accompanied by the potential for litigation. If
there might be legal action, it is important to have a professional
conduct the investigation even if it means bringing in an outside
Most common causes of accidents
Personal beliefs and feelings: Individual did not believe the accident
would happen to him or her; individual had personal problems that
clouded his or her judgment, etc.
Decision to work unsafely: Some people, for a variety of reasons,
feel it is in their best interest or to their benefit to work unsafely.
Mismatch or overload: Individual is in poor physical condition;
individual is fatigued, etc.
System failure: Lack of rules, regulations, procedures; failure to
correct known hazards; insufficient training for employees, etc.
Traps: Defective equipment; failure to provide, maintain, replace
proper personal protective equipment, etc.
Unsafe conditions: unsafe conditions created by the elements;
unsafe conditions created by a fellow employee, etc.
Unsafe acts: individual chooses to ignore the rules; individual uses
drugs or alcohol, etc.
Accident investigation guide
The investigation should be guided by the following words: who, what, when, where, why, and how.
Causes of the accidents should be the primary focus.
SME recommends the following questions:
What type of work was the injured person doing?
Exactly what was the injured person doing or trying to do at the time of the accident?
Was the injured person proficient in the task being performed at the time of the accident? Had the worker
received proper training?
Was the injured person authorized to use the equipment or perform the process involved in the accident?
Were there other workers present at the time of the accident? If so, who are they, and what were they
Was the task in question being performed according to properly approved procedures?
Was the proper equipment being used, including PPE?
Was the injured employee new to the job?
Was the process, equipment, or system involved new?
Was the injured person being supervised at the time of the accident?
Are there any established safety rules or procedures that were clearly not being followed?
Where did the accident take place?
What was the condition of the accident site at the time of the accident?
Had a similar accident occurred before? If so, were corrective measures recommended? Were they
Are there obvious solutions that would have prevented the accident?
The answers to these questions should be recorded. You may find it helpful to dictate your findings into a
micro-cassette recorder. This approach allows you to focus more time and energy on investigating and
less time on taking notes.
Safety personnel role in accident
If the accident is very minor, the injured employee’s supervisor may
conduct the investigation, but the safety and health professional
should at least study the accident report and be consulted regarding
recommendations for corrective action.
If the accident is so serious that it has widespread negative
implications in the community and beyond, responsibility for the
investigation may be given to a high level manager or corporate
executive. In such cases the safety and health professional should
assist in conducting the investigation.
If a company prefers the team approach, the safety and health
professional should be a member of the team and in most cases
should chair it.
Regardless of the approach preferred by a given company, the
safety and health professional should play a leadership role in
collecting and analyzing the facts and developing recommendations.
Steps for conducting an accident
Isolate the accident scene: This is done to keep curious onlookers
from removing, disturbing, or unknowingly destroying vital evidence.
Nothing but the injured worker should be removed from the scene.
Record all the evidence: As quickly as possible because certain
types of evidence may be perishable; accident scene may be
disturbed knowingly or unknowingly, pressure may mount to get a
critical piece of machinery back into operation. If in doubt, record it.
Photograph or videotape the scene: Both still and video cameras
must be on hand, loaded, and ready to use should an accident
occur. Place a ruler or coin next to the object when making a closeup photograph to get the object’s size or proper perspective.
Identify witnesses: Primary witness, secondary witness and tertiary
Interview witnesses: Primary witness first. May be necessary to reinterview witness.
Importance of recording all
• It is important to make a record of all pertinent evidence
as quickly as possible. There are 3 reasons for this:
• 1. Certain types of evidence may be perishable.
• 2. The longer an accident scene must be isolated, the
more likely it is that evidence will be disturbed, knowingly
• 3. If the isolated scene contains a critical piece of
equipment, pressure will quickly mount to get it back in
• Evidence can be recorded in a variety of ways including
written notes, sketches, photography, videotape, dictated
observations, and diagrams. In deciding what to record,
a good rule of thumb is, if in doubt record it.
Proper perspective of close-up
• A problem with photographs is that, by
themselves, they do not always reveal objects in
their proper perspective.
• The National Safety Council recommends that
when photographing objects involved in an
accident be sure to identify and measure them
to show the proper perspective. Place a ruler or
coin next to the object when making a close-up
photograph. This technique will help to
demonstrate the object’s size or perspective.
Three categories of witnesses to an
• In identifying witnesses, it is important to
compile a witness list.
• Names on the list should be recorded in three
• 1. Primary witness.
• 2. Secondary witness.
• 3. Tertiary witness.
• When compiling the witness list, ask employees
to provide names of all three types of witnesses.
When and where of interviewing
To ensure that the information is objective, accurate, and untainted
by the personal opinion and feelings of the witness, and able to be
When to interview: Immediately after the list has been compiled. The
witnesses recollection will be best right after the accident.
Immediacy also avoids the possibility of comparing notes and as a
result changing their story. Individuals should be interviewed
individually and separately, preferably before they have talked to
Where to interview: The best place to interview is at the accident
scene. Ensure that distractions are removed, interruptions are
guarded against, and witness is not accompanied by other
witnesses. If it is not possible to interview at the accident scene,
select a location that is not intimidating to the witness.
How to interview
The information being sought is who, when, where, why, and how.
The key to getting at the facts is to put the witness at ease and
Listen to what is said, how it is said, and what is not said.
Ask questions, but phrase them in an open ended format – “What
did you see?”
Do not lead the witness with your questions, and interrupt only if
Remain non judgmental and objective.
Ask witness to simulate rather than actually perform the steps that
led to the accident if possible. Record if possible and it is not
At the end of the interview summarize what you have heard and ask
have the witness verify your summary.
Purpose of an accident report
An accident investigation should culminate in a comprehensive
The purpose of the report is to record the findings of the accident
investigation, the cause of the accident, and recommendation for
According to OSHA document 2056 employers of 11 or more
employees must maintain records of occupational injuries and
illnesses as they occur.
If an accident results in the death of an employee or hospitalization
of 5 or more employees, a report must be submitted to the nearest
OSHA office within 48 hours. This rule applies regardless of the size
of the company.
The saddest part of non reporting of accidents is that they are not
investigated to determine and eliminate the cause.
More in the text book.
Accidents are investigated to identify causes, so that they can be
corrected, not to assign blame.
Accidents should be investigated as soon as possible so that
evidence and memories of witnesses are still fresh.
An accident investigation should ask the questions who, what,
when, where, and how.
A safety and health professional should play an active role in the
Steps in an accident investigation: isolate the accident scene,
record all evidence, photograph or video tape the accident scene,
identify witnesses, and interview witnesses.
Interviews should take place at the accident site whenever possible.
Ask open ended questions.
Accident report forms must meet the specifications of OSHA.
• Answer questions 2, 6, 7, 8, 11, and 12 on page 179180.
• 2. When should an investigation be reported? Why?
• 6. What role should the safety and health professional
play in the conduct of an accident investigation?
• 7. List and explain the steps for conducting an accident
• 8. Why is it important to record all pertinent evidence
relating to an accident immediately after an accident has
• 11. Briefly explain the when and where of interviewing
• 12. Briefly explain the how of interviewing witnesses.