The actual procedures used in a particular investigation depend on the nature and results of the incident. The agency having jurisdiction over the location determines the administrative procedures. In general, responsible officials will appoint an individual to be in charge of the investigation. The investigator uses most of the following steps:
- Define the scope of the investigation.
- Select the investigators. Assign specific tasks to each (preferably in writing).
- Present a preliminary briefing to the investigating team, including:
- Description of the incident, with damage estimates
- Normal operating procedures
- Maps (local and general)
- Location of the incident site
- List of witnesses
- Events that preceded the incident
- Visit the incident site to get updated Information.
- Inspect the incident site.
- Secure the area. Do not disturb the scene unless a hazard exists.
- Prepare the necessary sketches and photographs. Label each carefully and keep accurate records.
- Interview each victim and witness. Also interview those who were present before the incident and those who arrived at the site shortly after the incident. Keep accurate records of each interview. Use a tape recorder if desired and if approved.
- Determine what was not normal before the incident.
- Where the abnormality occurred
- When it was first noted
- How it occurred
- Analyze the data obtained in step 7. Repeat any of the prior steps, if necessary.
- Determine why the incident occurred.
- A likely sequence of events and probable causes (direct, indirect, basic)
- Alternative sequences
- Check each sequence against the data from step 7.
- Determine the most likely sequence of events and the most probable causes.
- Conduct a post-investigation briefing.
- Prepare a summary report, including the recommended actions to prevent a recurrence. Distribute the report according to applicable instructions.
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.
Gather evidence from many sources during an investigation. Get information from witnesses and reports as well as by observation. Interview witnesses as soon as possible after an incident. Inspect the incident site before any changes occur. Take photographs and make sketches of the incident scene. Record all pertinent data on maps. Get copies of all reports. Documents containing normal operating procedures, flow diagrams, maintenance charts, or reports of difficulties or abnormalities are particularly useful. Keep complete and accurate notes in a bound notebook. Record pre-incident conditions, the incident sequence, and post-incident conditions. In addition, document the location of victims, witnesses, machinery, energy sources, and hazardous materials.
In some investigations, a particular physical or chemical law, principle, or property may explain a sequence of events. Include laws in the notes taken during the investigation or in the later analysis of data. In addition, gather data during the investigation that may lend itself to analysis by these laws, principles, or properties. An appendix in the final report can include an extended discussion.
In general, experienced personnel should conduct interviews. If possible, the team assigned to this task should include an individual with a legal background. In conducting interviews, the team should:
- Appoint a speaker for the group.
- Get preliminary statements as soon as possible from all witnesses.
- Locate the position of each witness on a master chart (including the direction of view).
- Arrange for a convenient time and place to talk to each witness.
- Explain the purpose of the investigation (incident prevention) and put each witness at ease.
- Listen, let each witness speak freely, and be courteous and considerate.
- Take notes without distracting the witness. Use a tape recorder only with consent of the witness.
- Use sketches and diagrams to help the witness.
- Emphasize areas of direct observation. Label hearsay accordingly.
- Be sincere and do not argue with the witness.
- Record the exact words used by the witness to describe each observation. Do not “put words into a witness’ mouth.
- Word each question carefully and be sure the witness understands.
- Identify the qualifications of each witness (name, address, occupation, years of experience, etc.).
- Supply each witness with a copy of his or her statements. Signed statements are desirable.
After interviewing all witnesses, the team should analyze each witness’ statement. They may wish to re-interview one or more witnesses to confirm or clarify key points. While there may be inconsistencies in witnesses’ statements, investigators should assemble the available testimony into a logical order. Analyze this information along with data from the incident site.
Not all people react in the same manner to a particular stimulus. For example, a witness within close proximity to the incident may have an entirely different story from one who saw it at a distance. Some witnesses may also change their stories after they have discussed it with others. The reason for the change may be additional clues.
A witness who has had a traumatic experience may not be able to recall the details of the incident. A witness who has a vested interest in the results of the investigation may offer biased testimony. Finally, eyesight, hearing, reaction time, and the general condition of each witness may affect his or her powers of observation. A witness may omit entire sequences because of a failure to observe them or because their importance was not realized.
Problem Solving Techniques
Incidents represent problems that must be solved through investigations. Several formal procedures solve problems of any degree of complexity. This section discusses two of the most common procedures: Change Analysis and Job Safety 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:
- Define the problem (What happened?)
- Establish the norm (What should have happened?)
- Identify, locate, and describe the change (What, where, when, to what extent)
- Specify what was and what was not affected
- Identify the distinctive features of the change
- List the possible causes
- Select the most likely causes
Job Safety Analysis
Job safety analysis (JSA) is part of many existing incident 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 incident. 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 incident.
Report of Investigation
As noted earlier, an incident investigation is not complete until a report is prepared and submitted to proper authorities. Special report forms are available in many cases. Other instances may require a more extended report. Such reports are often very elaborate and may include a cover page, a title page, an abstract, a table of contents, a commentary or narrative portion, a discussion of probable causes, and a section on conclusions and recommendations.
The following outline has been found especially useful in developing the information to be included in the formal report:
- Background Information
- Where and when the incident occurred
- Who and what were involved
- Operating personnel and other witnesses
- Account of the Incident (what happened?)
- Sequence of events
- Extent of damage
- Incident type
- Agency or source (of energy or hazardous material)
- Discussion (Analysis of the Incident–how; why)
- Direct causes (energy sources; hazardous materials)
- Indirect causes (unsafe acts and conditions)
- Basic causes (management policies; personal or environmental factors)
- Recommendations (to prevent a recurrence) for immediate and long-range action to remedy:
- Basic causes
- Indirect causes
- Direct causes (such as reduced quantities or protective equipment or structures)
Thousands of incidents occur daily throughout the United States. These result from a failure of people, equipment, supplies, or surroundings to behave as expected. A successful incident investigation determines not only what happened, but also finds how and why the incident occurred. Investigations are an effort to prevent a similar or perhaps more disastrous sequence of events.
Most incident investigations follow formal procedures. This discussion covered two of the most common procedures: Change Analysis and Job Safety Analysis. An investigation is not complete however, until completion of a final report. Responsible officials can then use the resulting information and recommendations to prevent future incidents.