Theory of Occupational Accidents - Swiss Cheese Theory

According to Reason (1997) work accidents can occur due to the destruction of defenses made by the organization, so that the dangers that arise cannot be anticipated (Reason, 1997). All defenses formed by the organization are plans and actions to anticipate dangers that may arise, can be in the form of surveillance measures, protective equipment, regulations, and procedures, and so on.

Accidents can also occur due to the destruction of defenses coming from workers. Defense here, for example, workers who behave or commit unsafe acts in carrying out their work.

The defense established by the organization in general should fulfill the following functions:

1. Provide understanding and awareness of the dangers faced.
2. Provide guidance on safe operational activities.
3. Provide danger signs or warnings when danger arises.
4. Restore operational systems to a safe state.
5. Establish safety boundaries between hazards and possible losses.
6. Minimize the danger that occurs when the danger has passed through the established defense.
7. Avoid danger and perform rescue actions when danger arises.

The defense system should be made in such a way that each layer of defense can take care of each other. Ideally, a defense system has no gaps, but in fact in a defense system there are many gaps (Reason, 1997), such as Swiss cheese, where each sheet has many "holes". Indeed, each "hole" does not always cause an error or accident. Errors or accidents usually occur when the "holes" are in line and can be penetrated by a cause of error or accident.

Types of Defenses

Reason (1997) divides the form of defense into two types, namely the "hard" type defense and the "soft" type defense. The "hard" type of defense is a real and direct defense that workers can use. These types of defenses include (Reason, 1997):

1. Personal protective equipment
2. Safety equipment
3. First aid kit (P3K)
4. Good and well-maintained work

"Soft" type defense is a question that is not tangible, and its nature gives encouragement to workers to work safely. Defenses of this type include:

1. Organized site arrangement
2. Good schedule planning
3. Work safety rules and procedures
4. Supervision
5. Competence of workers
6. Safety banners and posters
7. Safe and comfortable working environment
8. Regulatory support actions
9. Safety meeting
10. Investigation of the causes of work accidents

Causes of Defense System Failure

Failure in the system can be caused by two things, namely active failure and latent failure (Reason, 1997).

1. Active failure is an unsafe action performed by someone who is directly related to the job, such as slips, lapses, mistakes, or procedural violation. Usually, this active failure has a direct effect on an event.
2. Latent failure is a "resident pathogen" in a system, this is caused by decisions taken by top-level management contained in the system, for a long period of time before interacting with active failure and local triggers that will later create a possible accident. Unlike active failure, this condition is often difficult to predict but can be identified and corrected before any unwanted events occur.

Work accident mechanism according to Swiss Cheese Model

The mechanism proposed by Reason (1997) describes how work accidents can occur in an organization or company. Work accidents can occur because the existing defense system has a "hole". This defense system can be in the form of trainings, procedures or regulations regarding work safety, provision of safety equipment, and others. 'Holes' in the defense system can be caused by unsafe actions and unsafe conditions. This unsafe action starts from work environment factors and organizational factors which are latent conditions that combine with unsafe actions of workers resulting in "holes" in the existing defense system and resulting in work accidents. Work environment factors and organizational factors are referred to as latent conditions because they can directly create holes in existing defense systems.

According to Reason (1997), basically, accidents occur due to weaknesses in the defense system depicted in four layers with holes. Four layers that make up the occurrence of an accident, namely (Reason, 1997):

Organizational Influences (the influence of organizing and management policies in the occurrence of accidents)

Resources/Management

1. Human Resources (HR): selection, placement, training
2. Finance: excessive cost cutting, lack of funds
3. Resource equipment/facilities: inadequate design, purchase of unsuitable equipment.

Organizational Climate

1. Organizational structure: chain of command, delegating authority, communication, clarity of responsibility.
2. Policy: punishment and reward, promotion, use of drugs and alcohol.
3. Culture: norms and rules, values and beliefs, fairness in running the organization.

Organizational Process

1. Operations: work schedule, yield pressure or time to complete work, incentives, measurement/appraisal, planning deficiencies.
2. Procedures: availability of procedures, standards, clarity of definitions and objectives, documentation, instructions.
3. Supervision: risk management and occupational safety and health programs.

Unsafe Supervision

Inadequate Supervision

Failing to provide guidance, failing to provide operational doctrine, failing to provide supervision, failing to provide training, failing to track qualifications, failing to track performance, planning not in accordance with the job: failing to provide correct data, failing to provide time to give instructions, the work not complying with rules/regulations, not providing adequate rest periods.

Failed to Fix Known Issues

Failing to correct document errors, failing to identify employees at risk, failing to initiate corrective action. failing to report unsafe tendencies. Violation of supervision: failing to enforce rules and regulations, giving authority to non-compliant employees.

Precondition For Unsafe Act

Employee Conditions

1. Mental state: disturbed attention, quick satisfaction, making distractions, mental fatigue, misplacing motivation.
2. Physical Condition: physical disorders, medical illnesses, physically suffering from disabilities, physical achievement.
3. Physical/mental limitations: lack of recreation, limited intellectual ability, limited physical ability.

Employee Skills

1. The organization does not provide training that suits its needs.
2. Employees do not "absorb" all training materials or employees are reluctant to attend training.

Unsafe Act (Unsafe Behavior or Actions Committed and Directly Related to the Occurrence of an Accident)

Error

1. Errors caused by weak skills.
2. Decision-making errors
3. Misperception.

Violation

1. Disobeying instructions.
2. Not using the tools, you should
3. Perform work beyond his authority.
4. Violating training regulations.
5. Doing overwork.
6. Not doing job preparation.
7. Get instructions from unauthorized people.
8. Work outside of where you should be.

Accident Control and Prevention According to the Swiss Cheese Model

According to Reason (1997), accidents can be prevented, and the number of accidents can be controlled by adding one or more layers of cheese to avoid holes (Reason, 1997). CRM (Crew Resource Management) and Safety Training is one of the efforts made by organizations or companies to reduce the weakness of each piece of cheese. In addition, workers should also add slices of cheese to themselves. Additions need to be made because each layer is a "defensive layer" in the process of possible accidents. The error allows the problem to pass through a hole in one layer, but in the next layer the hole is in a different place. Each slice of cheese is an opportunity to stop mistakes. The more defenses installed, the better. Also, fewer holes and smaller the holes, the more likely it is to catch or stop any errors that may occur.