Accident and Incident Theories: Comprehensive Strategies for Proactive Prevention, Lecture notes of Law

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ACCIDENT AND INCIDENT

THEORIES

Safety practitioners need to recognize several premises when addressing accident prevention:

• Accidents have causes.
• Accidents often involve hazards that include unsafe acts (activities), unsafe conditions, and other circumstances.
• Accidents may or may not have consequences.
• Consequences may be minor or major (severe). Understanding these points helps practitioners apply accident theories and models. Accident theories and models provide some insights when investigating accidents or conducting hazard and risk analysis aimed at prevention.

Serial and Parallel Theories

A parallel accident causation theory will look for combinations of items working together that lead to an accident. For example, suppose a driver had difficulty stopping a car when stepping on the brake pedal.

• A serial theory might learn that the driver’s foot slipped from the pedal.
• A parallel theory might find the foot slipping from a worn and slippery pedal.
• It may also find there was some wet substance on the sole of the driver’s shoe.
• In addition, the pedal material and sole material together may have created a low friction interface.

Single Factor Theories

Many people who deal with accident prevention look for a single or major cause for certain accidents. A single factor theory assumes that when one finds a cause, there is nothing more to find out. Very often the cause is the immediate or proximate cause, but that does not consider other elements that can contribute to the event.

• Single factor theories have limited value in prevention.
• Sometimes they are a hindrance to effective prevention.
• Most often there are other causes beside one immediate cause.
• Relying on a single factor theory will cause one to overlook other important preventive actions.

Energy Theory

William Haddon worked primarily in the prevention of vehicle accidents. He developed a theory that involves the transfer of energy, “the Energy Theory,” as a way to think about prevention. His approach is called “the Energy Release Theory.” The Energy Theory suggests that quantities of energy, means of energy transfer and rates of energy transfer relate to the kinds of injuries and severity of injuries. His theory helps resolve many safety engineering problems and offers a way to think about what can happen. Haddon’s approach involves a parallel theory of prevention. Multiple actions working concurrently can reduce the likelihood and severity of an accident.

Based on the energy transfer model, Haddon suggests ten strategies for preventing or reducing losses or consequences of accidents. The order for these strategies builds on potential accident sequences:

1. Prevent the marshaling of energy. In this strategy the goal is not producing energy or changing it to a form that cannot cause an accident or injury. Examples are substituting a safe substance for a dangerous one, not letting small children climb to levels above the floor, and not setting a vehicle in motion. 2. Reducing the amount of energy marshaled. Examples are keeping vehicle speeds down, reducing the quantities or concentration of high energy or toxic materials, limiting the height for objects, and reducing machine speed to the minimum needed during cleaning or maintenance of an unguarded machine. 3. Prevent the release of energy. Examples are using various means or devices to prevent elevators from falling, flammables from igniting, or foundations from being undercut by erosion. 4. Modify the rate of energy released from its source or modify the spatial distribution of the released energy. Slowing the burning rate of a substance or using an inhibitor and reducing the slope of roads are examples. 5. Separate in space or time the energy released from the potentially damaged structure or the potentially injured human. Examples include separate paths for vehicular and pedestrian traffic, placing electric power lines out of reach, using traffic signals to phase pedestrian and vehicular traffic, and using energy-absorbing materials.

Errors in Management Systems

Some involved with management methods believe that errors people make are management issues, not worker issues. Errors by workers are attributes of poor management processes. This concept is a critical part of management through quality espoused by Juran and Deming. Deming claimed that 85% of errors are due to poor processes. Only 15% of errors involve worker skills. He felt no matter how hard someone tries to improve within a given process, it is not possible unless there is a change in the process itself. He focused on management getting the processes right, reducing errors in poorly operating processes, and avoiding the need to make corrections after errors occur. Incidents and accidents are forms of errors, they interrupt processes and reduce quality. By engaging workers and managers to work together, it is possible to improve processes. Edward Deming

The management concepts of Deming and Juran are often called “Total Quality Management.” Their solution to bad processes was constant improvement. Today, the extension of their approach is called “Six Sigma.” Juran, defined critical processes as ones that present serious dangers to human life, health, and the environment or create losses of very large sums of money. Such processes require planning and design to reduce opportunities for human error to a minimum. Emphasis is on continuous improvement to achieve quality. That also emphasizes reducing accidents. Joseph M. Juran

The Three E’s of Safety

ACCIDENT UNSAFE ACT UNSAFE CONDITION EDUCATION ENFORCEMENT ENGINEERING The three E’s are engineering, education, and enforcement. Engineering primarily seeks to prevent unsafe conditions. Education primarily addresses unsafe acts. However, there are many training needs in safety that go beyond unsafe acts themselves. Engineers need to know how to recognize and control hazards in their designs. Workers and supervisors need to know how to recognize hazards on the job. They need to know which controls can help prevent accidents. Everyone needs to know which prevention strategies, policies and methods are in place. Enforcement applies to all aspects of accident prevention. It ensures implementing and complying with laws, regulation, standards, and policies. A fourth E, enthusiasm, is sometimes added to the first three E’s. It refers to motivating people to follow safe practices and contribute effectively to safety.

Concept-Driven Strategies

One can use accident theories and accident sequence models presented earlier in this chapter to help formulate accident prevention strategies.

Case-Driven Strategies: A

Reactive Approach

A reactive approach can be used to develop strategies for preventing accidents.

Comprehensive Strategies: A

Proactive Approach

An alternate approach is a proactive one. The aim is to identify all of the factors that can lead to accidents and the combinations of those factors.

High Cost Strategies

High Cost Another approach to prevention strategies looks at accident costs. A study of accident cases and insurance claims that applies principles such as the Vital Few can help focus on high cost events. Often high cost cases are high severity cases.

Combinations

Perhaps the best approach to accident prevention strategies involves a combination of approaches. Safety practice today requires the use of all approaches. Preventive strategies must use all the available tools to think about what can go wrong and how to prevent adverse events. The aim is to prevent accidents from happening at all. An effective strategy requires applying a broad range of knowledge. Examples are:

• past cases;
• cases reported by others;
• internal and national statistics;
• knowledge of hazards and controls;
• techniques for effectively motivating and working with people;
• an understanding of business goals and performance.

Safety Management Systems

The process involves employer representatives, employees, and a safety planning facilitator, often a safety practitioner. Each type of participant brings different viewpoints and experience to the process. The initial task is hazard identification. Participants apply information from the theories, models, and definitions above, along with other knowledge and experience. The next task is to conduct risk assessments on the identified hazards. Based on results, the participants select acceptable levels of risk and appropriate hazard controls. Each possibility needs evaluation to determine the potential for risk reduction. Then they test and implement one or more selected controls. The final task is to evaluate the effectiveness of implemented controls. The panel may apply the evaluation results in working through the process again.