Accident Theory
Health and Safety Management Systems are a key aspect to the day-to-day functioning of a business. As we discussed in the Leading and Lagging Indicators post, health and safety management systems that are proactive will have a much more effective and successful safety program. One of the fundamental approaches to proactive safety is to use a systems-failure approach to safety management, or “accident theory”.
Accident Theory, in a health and safety context, is the study of failures within a management system or human error, and allows safety professionals to better understand why accidents happen and how to design a management system to prevent them. While this may seem reactive, as you would trace your way back from an accident, using both accident theory and work experience will allow the safety professional to “predict” accidents or reduce the severity of future accidents. The combination of practical experience and accident theory allows for a more thorough investigation, and provides the safety professional with the tools to address the root cause(s) of accidents before they cause injury.
Six factors provide the basis of the various models within accident theory. These factors are; management, behaviour, psychology, energy, decision, and safety systems. I will provide a brief overview of each of the specific models and what they theorize to be the causes of accidents.
Management Models
For management models, the idea is that there is a capacity within management to prevent accidents and incidents through a “Domino” effect. Domino models are also known as sequential linear accident models and go off the theory that if you remove on of the “Dominos” you can prevent the incident. The oldest model to use this approach is one by Herbert Heinrich, called the Heinrich Management Model.
Heinrich’s Management Model
This model, by today’s standards, is outdated as it assumes that unsafe acts of employees occur because of personality traits and conditions of upbringing. It ignores the presence of workplace factors, such as unsafe conditions, that are within control of the employer as well as ignoring employer obligations to provide training and supervision to ensure a safe workplace.
The process of this model suggests:
Social Environment/Ancestry —> Fault of Person —> Unsafe Act/Condition —> Accident —> Injury
Bird’s Loss Causation Model
An expansion to Heinrich’s model, Frank Bird indicated that accidents are caused by a lack of management control. For an accident to occur, key individuals within the organization did something or failed to do something that ultimately resulted in the accident. This could be caused by a lack of control by management, lack of knowledge, inadequate supervisor or equipment, and unsafe practices/conditions.
This model suggests:
Lack of Control —> Basic Cause(s) —> Immediate Cause(s) —> Incident —> Injury or Damage
Adams’ Management Model
Further emphasizing managements role, the Adam’s Management Model focuses on management failures leading to problems with supervisor conduct, affecting enforcement of rules within the workplace. Poor management structure leads to an atmosphere of negative coaching, leading to errors and affecting long-term morale.
Behaviour-Based Safety Models
Safety models that focus on the behaviour of the workers will study human error and it’s impact on workplace accidents. The ABC model (which stands for Activators, Behaviours, and Consequences) proposed by Geller, focuses on human behaviour and the modification of it to prevent accidents. This model is also the root of the modern “Behaviour-Based Model” (BBS) widely used in current safety systems. BBS applies behavioural changes to real types of workplaces, focusing on why workers do what they do and applies a feedback process to improve how they work. This model links a worker’s physical and mental attitude to how well they execute their responsibilities at work. The more the workers values align with that of the company, the attitudes can be shaped to reduce “at-risk” behaviours, lowering the number of accidents.
Psychological Models
Psychological models of accident theory consider mental and emotional factors and their effect on workplace accidents. The models suggest that accidents are caused by a low level of alertness in the workers, not from external factors in the workplace. It theorizes that by engaging workers at a more meaningful level in their jobs will improve their performance and reduce accident risk.
Energy Models
Energy models focus in terms of high-energy sources and barriers that are between the source and the worker, as energy is a common cause of workplace accidents. Models that follow this theory will assume that hazards involve some level of energy and that the direct causes of accidents are an unplanned release of energy. It also suggests that the indirect causes are unsafe acts or conditions.
Decision Models
Decision models focus on a sequence of events that can success or fail in order for an accident to occur or not occur. This includes a build-up and release of danger as well as how workers perceive, recognize, and react to avoid an accident. Decision models are best applied to process related accidents as it relates the factors leading up to the incident strictly to the process design or engineering and puts less emphasis on behaviour.
Safety Systems Models
A form of engineering models, safety systems models will focus on identifying and separating hazards from the individual by a series of “defences”. James Reason created the “Swiss Cheese” model in that the holes within the Swiss cheese are weaknesses within the system that allow hazards through the defences, leading to accidents. So, if continuous interventions are not maintained to keep the system defences strong, the “holes” will grow and increase the likelihood of hazards getting through, and resulting in increased incidents.
Applying Accident Theory in Safety Management Systems
By recognizing and investigated the causes of incidents, safety professionals are able to build systems that are effective and tuned to their workplace. Through the review and improvement, or development, of a safety management system, the safety professional should apply or use multiple models. By constraining ourselves to one specific model, we limit the flexibility and scope of understanding why an incident has or could occur. With the understanding that incidents are rarely, if ever, the result of a single cause or source, we can use multiple models to assess each failure within the management system that resulted in, could result in, an unwanted event.
With a strong understanding of accident theory, the safety professional is more effective at understanding the causes of incidents, and helps to develop a broader knowledge of workplace risks and hazards to address all work situations. By designing a program to address work force stressors, using employee selection, training, education, supervision and mentoring, we are able to ensure the long-term goal of continuous improvement of a health and safety management system and to reduce the frequency and severity of incidents.
References:
https://www.ohsbok.org.au/wp-content/uploads/2019/07/32-Models-of-Causation-Safety.pdf
https://wps.prenhall.com/chet_goetsch_occupation_7/139/35769/9157107.cw/index.html