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Process Of Developing A Sequence Of Events Leading Up To The Accident Event

Develop the Sequence of Events

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So far, you have collected a lot of factual data and it’s strewn all over your desk. The task now is to turn that data into useful information. You’ve got to somehow take this data and make some sense of it.

Assessment vs. Analysis

It’s important to know that you’re not gathering all of this information just to conduct an assessment of what was and was not present immediately prior to the accident. You’re actually conducting an analysis to determine specifically how surface causes (behaviors and conditions), and the underlying root causes (system weaknesses) contributed to the accident. To better understand this, let’s take a closer look at what the process of “analysis” is.

Analysis Defined

Webster defines analysis as the “separation of an intellectual or substantial whole into its parts for individual study.”

The accident is a complicated process of individual events leading up to and including the main event. When an accident occurs, we need to separate or “break down” the “whole” accident into its component “parts” for study to determine how they contributed to the accident: the main event.

The accident investigator’s challenge is to effectively assess each event to identify the presence or absence of behaviors and conditions and then analyze those behaviors and conditions in each event to determine if and how they contributed to the accident. To do this we need to make some basic assumptions about the factors that cause or contribute to accidents.

The Reasons for Preventing Accidents

Conduct Event Analysis

Analyzing Each Event

In developing a sequence of events, the challenge is to take the information gathered and arrange it so that we can accurately determine what initial conditions and/or actions transformed the planned work process into an unintended accident process.

The two components of an event: The Actor and the Action

Each event in the unplanned accident process is composed of an actor and an action, so let’s take a look at each.

  1. Actor: The actor is an individual or object that directly influenced the flow of the sequence of events. An actor may participate in the process or merely observe the process. An actor initiates a change by performing or failing to perform an action.
  2. Action: An action is “the something” that is done by an actor. Actions may or may not be observable. An action may describe a behavior that is accomplished or not accomplished. Failure to act should be thought of as an act, just as much as an act that is accomplished.

It’s important to understand that when describing an event in writing, first identify the actor and then tell what the actor did. Remember, the actor is the “doer,” not the person or object being acted upon or otherwise having something done to them. For instance, take a look at the event statement below:

“Bob unhooked the lifeline from the harness.”

In the example above, “Bob” is the actor, and “unhooked” describes the action. First, we describe the actor…Bob. Next, we describe the action…unhooking. The lifeline and harness, although “objects” are not actors because they are not performing an action. Rather, something is being done to them. Also, note that the statement is written in the active tense.

Developing the sequence

Our challenge at this point in the investigation process is to accurately arrange the events to determine their correct sequence leading up to the accident so that we can more effectively understand why the accident event, itself, happened. Once the sequence of events is developed, we can then study each event in the sequence to determine the related causal factors below.

  • Hazardous conditions: Objects and physical states that directly caused or contributed to the accident.
  • Unsafe behaviors: Actions taken/not taken that directly caused or contributed to the accident.
  • System weaknesses: Underlying inadequate or missing policies, programs, plans, processes, procedures and practices that contributed to the accident.

Sample Sequence of Events

To get a good idea of what the sequence of events looks like, review the short example below:

  1. At approximately 12:45 PM employee #1 began dumping accumulated sand from an irrigation mainline pipe.
  2. Employee #1 oriented the pipe vertically and it contacted a high voltage power line directly over the work area.
  3. Employee #2 heard a ‘ zap’ and turned to see the pipe falling and employee #1 falling into an irrigation ditch.
  4. Employee #2 ran to employee #1 and pulled him from the irrigation ditch.
  5. Approximately one minute later, paramedics arrived and began to administer CPR on employee #1.
  6. At approximately 1:10 PM an ambulance arrived and transported employee #1 to the hospital where he was pronounced dead at 1:30 PM.

Paint a Word Picture

It’s important the sequence of events clearly describe what occurred so someone who is unfamiliar with an accident is able to “see it happen” as they read the narrative.

Paint a Word Picture
You can use cards to develop the sequence of events.

Sample Sequence of Events

Click on the image to the right to see how you can use cards to visually develop the sequences of events. Describe each single event on the front of the card and any additional source information on the back. Each card will indicate the actor and action. Attach any photos you take to the card. Arrange the cards on your desk or a wall in the proper sequence.

Construct One Event Only

If an event is hard to understand, it may be that the description is too vague or general. The solution to this problem is to increase the detail. We can use two strategies to increase detail:

  1. Look around: Determine if anything else was said/done before or after the event you’ re currently assessing.
  2. Separate the actors: Remember, an actor may be a person or a thing accomplishing a given action. If an event includes actions by more than one actor, break the event down into two events. If the event contains the conjunction, “and,” the event is likely to be a combination of two events. If you look at the sample sequence of the events from 5.9 and 5.10, I’m sure you can spot a few combined events.

Well, that was a short, but informative, introduction to the idea of constructing the sequence of events. Just remember, the accuracy of your investigation will be greater by following this procedure. It is now time to answer your final quiz question and check your answers below.


Accident Investigation Quiz

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