Instructions to Investigators

The steps involved in investigating an incident?
The incident investigation process involves the following steps:

  • Report the incident occurrence to the HSEA or appropriate designated person within the College
  • Provide first aid and medical care to injured person(s) and prevent further injuries or damage
  • Investigate the incident
  • Identify the causes
  • Report the findings
  • Develop a plan for corrective action
  • Implement the plan
  • Evaluate the effectiveness of the corrective action
  • Make changes for continuous improvement

As little time as possible should be lost between the moment of an incident or near miss and the beginning of the investigation. In this way, one is most likely to be able to observe the conditions as they were at the time, prevent disturbance of evidence, and identify witnesses. The investigator’s kit should be immediately available so that no time is wasted.
Incident Investigation Kit

To assist JOHSCs with the investigation process an Incident Investigation Kit will be available from Regional Administration upon request if required.  This kit is available as a resource for Incidents of a serious nature.
Investigation Kit:

  • Digital camera or disposable camera with flash
  • tape measure - 15m
  • clipboard and pad
  • ruler
  • pencil and pens
  • flashlight
  • chalk (yellow and white)
  • ten 4 inch spikes
  • surveyors tape 15m - red
  • accident investigation form
  • a copy of these instructions


Investigation Procedure for a Serious Incident

The personnel conducting the investigation will:

  • Pick up the Incident Investigation Kit.
  • Get the big picture as to what happened.
  • Examine the materials, equipment, tools, etc, involved.
  • Take photos, draw pictures, get measurements, etc.
  • List all people involved, interview these people and get written statements as to what happened, get the facts.
  • Analyze all available information and determine causes.
  • Look for causes where "the system failed the worker" don't just look for "where the worker failed the system".
  • Determine correct actions that will prevent reoccurrence.
  • Provide recommendations to the employer to implement the corrective actions.
  • Recommendations are entered into JOHSC minutes and posted on the safety board at the appropriate campus
  • An investigation is only closed off when all resultant actions are complete.

What should be looked at as the cause of an incident?
Incident Causation Models
Many models of incident causation have been proposed, ranging from Heinrich's domino theory to the sophisticated Management Oversight and Risk Tree (MORT).
The simple model shown in Figure 1 attempts to illustrate that the causes of any incident can be grouped into five categories - task, material, environment, personnel, and management. When this model is used, possible causes in each category should be investigated. Each category is examined more closely below. Remember that these are sample questions only: no attempt has been made to develop a comprehensive checklist.

Figure 1 - Incident Causation Model

The actual work procedure being used at the time of the incident must be explored. Members of the incident investigation team will look for answers to questions such as:


  • Was a safe work procedure used?
  • Had conditions changed to make the normal procedure unsafe?
  • Were the appropriate tools and materials available?
  • Were they used appropriately for the task(s) performed?
  • Were safety devices working properly? Was work being performed if they were not?
  • Was lockout used when necessary? Was correct lockout procedure followed?

For most of these questions, an important follow-up question is "If not, why not?"
To seek out possible causes resulting from the equipment and materials used, investigators might ask:

  • Was there an equipment failure?
  • What caused it to fail?
  • Was the machinery poorly designed?
  • Was the equipment maintained correctly according to manufacturer’s directions or industry standards?
  • Were hazardous substances involved?
  • Were they clearly identified?
  • Was a less hazardous alternative substance possible and available?
  • Was the raw material substandard in some way?
  • Should personal protective equipment (PPE) have been used?
  • Was the PPE used?
  • Were users of PPE properly trained?

Again, each time the answer reveals an unsafe condition, the investigator must ask why this situation was allowed to exist.
The physical environment, and especially sudden changes to that environment, are factors that need to be identified. The situation at the time of the incident is what is important, not what the "usual" conditions were. For example, incident investigators may want to know:

  • 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 toxic or hazardous gases, dusts, or fumes present?

The investigator must not all possible environmental factors that may have contributed to the incident. Often weather conditions are only noted for traffic incidents and not always considered for a workplace incident.
The physical and mental condition of those individuals directly involved in the event must be explored. The purpose for investigating the incident is not to establish blame against someone but the inquiry will not be complete unless personal characteristics are considered. Some factors will remain essentially constant while others may vary from day to day:

  • Was the worker a “New Worker”? Was the worker on the job less than 30 days?
  • Were workers experienced in the work being done?
  • Had they been adequately trained? Is there supporting documentation?
  • Can they physically do the work?
  • What was the status of their health?
  • Were they tired? Were there previous indicators of being fatigued prior to work commencing?
  • Were they under stress (work or personal)?

Northern Lights College holds the legal responsibility for the safety of the workplace and therefore the role of supervisors and higher management and the role or presence of management systems must always be considered in an incident investigation. Failures of management systems are often found to be direct or indirect factors in incidents. Ask questions such as:

  • Were the appropriate safety rules communicated to and understood by all workers and/or students?
  • Were written procedures and orientation available?
  • Were they being enforced?
  • Was there adequate supervision?
  • Were workers trained to do the work? Were the students trained in the safe processes?
  • Had hazards been previously identified?
  • Had procedures been developed to overcome them?
  • Were unsafe conditions corrected?
  • Was regular maintenance of equipment carried out?
  • Were regular safety inspections carried out?

This model of incident investigations provides a guide for uncovering all possible causes and reduces the likelihood of looking at facts in isolation. Some investigators may prefer to place some of the sample questions in different categories; however, the categories are not important, as long as each pertinent question is asked. Obviously there is considerable overlap between categories; this reflects the situation in real life.

*Note* Unless dependable and accurate documentation exists to substantiate the submissions by any worker of compliance, than such compliance does not exist!
The above sample questions do not make up a complete checklist, but are examples only.

How are the facts collected?

The steps in incident investigation are simple: the incident investigators gather information, analyze it, draw conclusions, and make recommendations. Although the procedures are straightforward, each step can have its pitfalls.As mentioned above, an open mind is necessary in incident 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 conclusions should not be drawn until all the information is gathered.


Physical Evidence

Before attempting to gather information, the site should be examined for a quick overview. Steps must be taken to preserve evidence, and identify all witnesses. In some jurisdictions, an incident site must not be disturbed without prior approval from appropriate government officials such as the coroner, inspector, or police. In the event of a fatality nothing can be moved until permission from WorkSafeBC and the RCMP has been granted.

 Physical evidence is probably the most non-controversial information available. It is also subject to rapid change or obliteration; therefore, it should be the first to be recorded. The following items need to be recorded as soon as possible. If the worksite cannot be entered for whatever reason sketches of the scene and digital photographs at as many angles as practicable are required.

  • positions of injured workers
  • equipment being used
  • materials or chemicals being used
  • safety devices in use
  • position of appropriate guards
  • position of controls of machinery
  • damage to equipment
  • housekeeping of area
  • weather conditions
  • lighting levels
  • noise levels
  • time of day


Before anything is moved or altered photographs must be taken of the area. Perspective shots (using something like a ruler to define height, width and length) and close up images of specific areas that may help to reveal causality will be required. Sketches of the incident scene based on measurements taken may also help in subsequent analysis and will clarify any written reports. Broken equipment, debris, and samples of materials involved may be removed for further analysis by appropriate experts. Even if photographs are taken, written notes about the location of these items at the incident scene must be prepared, the written noted will be of assistance if any later depositions are required.


Eyewitness Accounts

Although there may be occasions when it is not practical to do so, every effort should be made to interview witnesses. In some situations witnesses may be theprimary source of information because safety personnel may be called upon to investigate an incident without being able to examine the scene immediately after the event.
Witnesses may be under severe emotional stress or afraid to be completely open for fear of recrimination, interviewing witnesses is probably the hardest task facing an investigator.
Witnesses should be kept apart and interviewed as soon as possible after the incident. If witnesses have an opportunity to discuss the event among themselves, individual perceptions may be lost in the normal process of accepting a consensus view where doubt exists about the facts. In other words available witnesses may s
Witnesses should be interviewed alone, rather than in a group. An investigator may decide to interview a witness at the scene of the incident where it is easier to establish the positions of each person involved and to obtain a description of the events. On the other hand, it may be preferable to carry out interviews in a quiet office where there will be fewer distractions. The decision may depend in part on the nature of the incident and the mental state of the witnesses.


Interviewing is an art that cannot be given justice in a brief document such as this, but a few do's and don'ts can be mentioned. The purpose of the interview is to establish an understanding with the witness and to obtain his or her own words describing the event:


  • put the witness, who is probably upset, at ease
  • emphasize the real reason for the investigation, to determine what happened and why
  • let the witness talk, listen
  • confirm that you have the statement correct
  • try to sense any underlying feelings of the witness
  • make short notes or ask someone else on the team to take them during the interview
  • ask if it is okay to record the interview, if you are doing so
  • close on a positive note



  • intimidate the witness
  • interrupt
  • prompt
  • ask leading questions
  • show your own emotions
  • jump to conclusions

The investigator should ask open-ended questions that cannot be answered by simply "yes" or "no". The actual questions asked of the witness will naturally vary with each incident, but there are some general questions that should be asked each time:

  • Where were you at the time of the incident?
  • What were you doing at the time?
  • What did you see, hear?
  • What were the environmental conditions (weather, light, noise, etc.) at the time?
  • What was (were) the injured worker(s) doing at the time?
  • In your opinion, what caused the incident?
  • How might similar incidents be prevented in the future?


The investigator was likely not at the scene at the time, asking questions is a straightforward approach to establishing what happened. Obviously, care must be taken to assess the credibility of any statements made in the interviews. Answers to a first few questions will generally show how well the witness could actually observe what happened.
Another technique sometimes used to determine the sequence of events is to re-enact or replay them as they happened. Obviously, great care must be taken so that further injury or damage does not occur. A witness (usually the injured worker) is asked to reenact in slow motion the actions that preceded the incident.

Background Information

A third, and often an overlooked source of information, can be found in documents such as technical data sheets, JOHSC minutes, inspection reports, NLC policies, maintenance reports, past incident reports, formalized safe-work procedures, and training reports.
Any pertinent information should be studied to see what might have happened, and what changes might be recommended to prevent recurrence of similar incidents. It will be the responsibility of the investigator to gather all of the necessary pertinent information.

What an investigator should know when making the analysis and conclusions?

At this stage of the investigation most of the facts about what happened and how it happened should be known. This has taken considerable effort to accomplish but it represents only the first half of the objective. Now comes the key question--why did it happen? To prevent recurrences of similar incidents, the investigators must find all possible answers to this question.
A good investigator has kept an open mind to all possibilities and looked for all pertinent facts. There may still be gaps in the understanding of the sequence of events that resulted in the incident. There may be a need to re-interview some witnesses to fill these gaps and complete the sequence of events.
When the analysis is complete, the investigator(s) must write down a step-by-step account of what happened (their conclusions) working back from the moment of the incident, listing all possible causes at each step. This is not extra work: it is a draft for part of the final report. Each conclusion should be checked to see if:

  • it is supported by evidence
  • the evidence is direct (physical or documentary) or based on eyewitness accounts, or
  • the evidence is based on assumption.


This list serves as a final check on discrepancies that should be explained or eliminated.

Why should recommendations be made?

The most important final step is to come up with a set of well-considered recommendations designed to prevent recurrences of similar incidents. Once reasonable conclusions have be made as to the events that transpired it should not be too difficult to come up with realistic recommendations. Recommendations should:

  • be specific
  • be constructive
  • get at root causes
  • be practicable
  • identify contributing factors

The investigating party and JOHSC will have to resist the temptation to make only general recommendations to save time and effort. It is important to make recommendations specific and prescriptive wherever possible.

 For example, it has been determined that a blind corner contributed to an incident. Rather than just recommending "eliminate blind corners" it would be better to suggest:

Install mirrors at the northwest corner of building X (specific to this incident) install mirrors at blind corners where required throughout the worksite (general)

Investigating parties and/or JOHSCs will never make recommendations about disciplining a person or persons who may have been at fault. This would not only be counter to the real purpose of the investigation, but it would jeopardize the chances for a free flow of information in future incident investigations.
In the unlikely event that the investigator(s) have not been able to determine the causes of an incident with any certainty, safety weaknesses in the operation have likely been uncovered. It is appropriate that recommendations be made to correct these deficiencies.

The Written Report

All incidents should be initially reported using the Northern Lights College Near Miss/Incident Reporting Form. Once the investigation has been completed the compiled notes, information, statements and digital material will be entered into the form. It is important to list all material on the form that is included as evidence or supporting statements.
A file will be maintained by the HSEA and the file will consist of:

  • The finished Near Miss/Incident Reporting Form
  • All written notes from the investigating party members
  • Any written statements provided by witnesses or involved parties
  • All sketches and diagrams
  • Any printed photographs

It is important to remember that readers of the report do not have the intimate knowledge of the incident the writer will have to include all pertinent details. Photographs and diagrams may save many words of description. Identify clearly where evidence is based on certain facts, eyewitness accounts, or your assumptions.  If doubt exists about any particular part, this should be stated clearly. The reasons for any conclusions should be stated and followed by any recommendations. Any recommendations must be followed up by an official Recommendation to Employer. The investigator(s) should weed out extra material that is not required for a full understanding of the incident and its causes such as photographs that are not relevant and parts of the investigation that led you nowhere.
The measure of a good incident report is quality, not quantity. All findings must be communicated with workers, supervisors and management.
The findings will be published and posted on the safety bulletin boards at the campuses along with the JOHSC minutes. The information will be presented 'in context' so everyone understands how the incident occurred and the actions in place to prevent it from happening again. The report must be specific in the intent of prevention not the allocation of blame. The “public” report will be sanitized so that names of the involved workers and witnesses will be protected and privacy respected.

What should be done if the investigation reveals "human error"?

A difficulty that has bothered many investigators is the idea that one does not want to lay blame. However, when a thorough worksite incident investigation reveals that some person or persons among management, supervisor, and the workers were apparently at fault, then this fact should be pointed out. The intention here is to remedy the situation, not to discipline an individual.  In a majority of cases retraining or remedial training might be the only requirement.
Failing to point out human failings that contributed to an incident will not only downgrade the quality of the investigation, it will also allow future INCIDENTs to happen from similar causes because they have not been addressed.
If the investigation reveals the possibility of obvious negligence or blatant disregard for safety by the worker(s) involved, a copy of the file must be turned over to the Human Resources Dept.

How should follow-up be handled?

Management is responsible for acting on the recommendations in the incident investigation report. The JOHSC will monitor the progress of these actions.
Follow-up actions include:

  • Respond to the recommendations in the report by explaining what can and cannot be done (and why or why not).
  • Develop a timetable for corrective actions.
  • Monitor that the scheduled actions have been completed.
  • Inform and train other workers at risk.
  • Re-orient worker(s) on their return to work.




WorkSafeBC .com
Workers’ Compensation Act - BC WCA Part 3 Division 10 Sections 172-177
Occupational Health and Safety Regulation - BC OHSR Part 3 Section 3.4 Incident investigation reports

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