Accident Theories for Accident Prevention

Summary

In this presentation, Azman Abdul Rahman explores theories and models developed by safety experts to understand and prevent accidents. Key topics include the classification of accidents and incidents, the accident triangle ratio, and the causes of accidents. The presentation delves into the domino theory of accident causation and the importance of root cause analysis in preventing recurrence. The speaker emphasizes the application of these theories to workplace safety programs, suggesting a combination of theories and models for effective problem-solving.

Takeaways

• 📚 Accidents and incidents are two different concepts: Accidents result in injury or damage, while incidents have the potential but do not cause actual harm.
• 🔍 Unsafe acts and conditions are significant contributors to workplace accidents, with acts like horseplay and conditions like slippery floors posing risks.
• 📊 The accident triangle, introduced by Heinrich, illustrates the relationship between minor injuries, serious injuries, and near misses, suggesting that reducing minor incidents can lead to fewer major accidents.
• 👷‍♂️ Unsafe acts are often caused by human error, which can be influenced by factors like training, attitudes, and fatigue.
• 🏗️ Unsafe conditions can result from inadequate housekeeping, improper storage, or defective equipment, and are often a consequence of human actions.
• 🔑 Root cause analysis is crucial for preventing accidents by identifying and addressing the underlying causes rather than just the immediate symptoms.
• 💡 Maslow's Hierarchy of Needs provides insight into human motivation and behavior, which is important for managing safety in the workplace.
• 🌐 The iceberg model demonstrates that direct costs of accidents are often just the tip, with indirect costs like legal fees and lost business potentially much higher.
• 🛠️ Equipment suitability, proper handling of substances, and safe operating procedures are key components of a safe workplace.
• 🔄 Theories of accident causation, such as the domino theory and multiple factors theory, offer different perspectives on why accidents occur and how they can be prevented.

Q & A

What is the main purpose of the presentation by Azman Abdul Rahman?

The main purpose of the presentation is to provide an understanding of various theories and models developed by safety experts to prevent accidents by addressing unsafe acts and conditions.

How are accidents and incidents differentiated according to the presentation?

Accidents are unplanned and unexpected events that result in loss, injury, or damage, while incidents are similar events that have the potential to cause harm but do not actually result in injury or damage.

What is the significance of the accident triangle ratio introduced by Heinrich?

Heinrich's accident triangle ratio suggests that for every 300 near misses, there will be 29 minor injuries and one major injury, indicating the importance of addressing minor accidents to prevent major ones.

What is the role of unsafe acts and conditions in causing accidents as per the presentation?

Unsafe acts are actions by people that are not safe, such as horseplay or not using PPE, while unsafe conditions are workplace conditions that could cause injury or damage, like missing machine guards or slippery floors.

How does the presentation describe the relationship between near-misses and accidents?

The presentation describes near-misses as incidents that have the potential to cause injury or damage but do not, and that they are precursors to accidents, which do result in injury or damage.

What is the iceberg model mentioned in the presentation, and how does it relate to accident costs?

The iceberg model represents the costs of accidents, with direct costs being the visible tip and indirect costs being the larger, hidden portion beneath the surface, which can be significantly higher.

According to the presentation, what are the four main factors that contribute to workplace injuries?

The four main factors contributing to workplace injuries are environment, equipment and materials, system and procedure, and worker factors such as training, skills, and attitudes.

What is the domino theory of accident causation as presented by Heinrich?

Heinrich's domino theory suggests that accidents result from a chain of sequential events, and by removing one of the dominoes, typically an unsafe act, the chain can be broken to prevent accidents.

How does Bird's update of the domino theory differ from Heinrich's original model?

Bird's update introduces the concept of management failure as a leading cause of accidents, emphasizing the role of inadequate systems, standards, and compliance by management in the chain of events leading to accidents.

What is the difference between root cause and basic cause in the context of accident analysis?

Root cause is the most fundamental cause that, if corrected, can prevent the recurrence of an error, such as poor safety management or lack of training. Basic cause refers to the underlying reasons for unsafe acts or conditions.

Why is root cause analysis important in accident prevention programs?

Root cause analysis is important because it identifies the fundamental causes of accidents, allowing for corrective actions that can prevent recurrence, rather than just addressing symptoms.

Outlines

00:00

📚 Introduction to Accident Theories and Models

Azman Abdul Rahman introduces various theories and models developed by safety experts to understand how accidents occur. These theories form the basis for accident prevention programs aimed at preventing unsafe acts and conditions. The presentation will cover the classification of accidents and incidents, the accident triangle ratio, causes of accidents, accident causation theories, and root cause analysis. The importance of applying these theories in workplace accident prevention is emphasized, suggesting that a combination of theories and models may offer the best approach to problem-solving. The difference between accidents and incidents is clarified, with accidents resulting in injury or damage and incidents having the potential but not causing harm.

05:00

🔍 Accident Classification and Heinrich's Theory

The script discusses how accidents can be classified by the extent of injury or property damage. Unsafe acts and conditions are identified as common causes of accidents. A near-miss is defined as an incident with potential for harm but no actual injury or damage. The concept of property damage due to negligence or acts of nature is introduced. The accident triangle, introduced by Herbert William Heinrich in 1931, illustrates the relationship between serious injuries, minor injuries, and no injuries in accidents. Heinrich's study suggests that for every 300 near-misses, there will be 29 minor injuries and one major injury, implying that reducing minor accidents can lead to a decrease in major accidents. Frank E Bird later refined the theory, proposing a different ratio based on a larger dataset.

10:06

🧠 Human Factors in Accident Causation

The script emphasizes that accidents are caused by a combination of factors, including unsafe acts and conditions. Heinrich's studies indicate that 88% of accidents are due to unsafe actions, 10% due to unsafe conditions, and only 2% by uncontrolled factors. The shift in safety management from engineering to managing human error is highlighted, with human behavior becoming a crucial aspect of workplace safety. Abraham Maslow's Hierarchy of Needs is introduced as a model to understand human motivation, which includes physiological, security, belonging, esteem, and self-actualization needs. Employers are advised to be aware of contributing factors in their workplace, such as equipment suitability, substance handling, safe operating procedures, and environmental conditions.

15:10

🏥 The Domino Theory and Accident Prevention

Herbert W. Heinrich's domino theory is presented, which suggests that accidents result from a chain of sequential events. The theory identifies injury, accident, unsafe act/condition, and person's fault as the dominoes that lead to an accident. The theory emphasizes the importance of preventing unsafe acts and conditions to avoid accidents. Bird and Loftus later updated the domino theory, adding management failure as a leading cause of accidents and suggesting that effective safety programs can prevent them. The script provides an example of how the updated domino model can be applied to analyze an accident involving a stamping machine, highlighting the importance of management's role in accident prevention.

20:13

🔬 Root Cause Analysis in Accident Investigation

The final paragraph discusses root cause analysis as a systematic process for identifying the underlying causes of problems or events and developing action plans to address them. It differentiates between basic or root causes, contributing causes, and direct causes, explaining that focusing only on the latter two may not prevent recurrence. Root cause analysis aims to answer key questions about what happened, how, and why, and what needs correction. The tools necessary for conducting root cause analysis are mentioned, and the presentation concludes with a hope that the information will aid in developing effective workplace accident prevention programs.

Keywords

💡Accident

An accident, as defined in the script, is an unplanned and unexpected event that results in loss of life, injury, property damage, or environmental harm. It is a core concept in the video as it sets the stage for discussing safety theories and prevention strategies. For instance, the script differentiates between accidents and incidents, highlighting that while both are unplanned, accidents lead to tangible harm.

💡Incident

An incident is an unplanned and unexpected event that has the potential to cause injury, illness, or property damage but does not necessarily result in such outcomes. It is often referred to as a near-miss. The script uses the term to illustrate the precursor to an accident, emphasizing the importance of addressing incidents to prevent accidents.

💡Unsafe Acts and Conditions

Unsafe acts are actions by individuals that pose a risk, such as not using personal protective equipment or violating safety rules. Unsafe conditions refer to hazardous workplace environments, like missing machine guards or slippery floors. The script underscores that both unsafe acts and conditions are key contributors to accidents and are thus focal points for prevention efforts.

💡Accident Triangle

The accident triangle, introduced by Herbert William Heinrich, illustrates the relationship between the number of accidents resulting in serious injury, minor injuries, or no injuries. The script uses this concept to explain the ratio of incidents to accidents, suggesting that a focus on reducing minor accidents can lead to a decrease in major accidents.

💡Root Cause Analysis

Root cause analysis is a systematic process for identifying the underlying causes of an accident or problem to prevent recurrence. The script highlights its importance in distinguishing between the root cause, which addresses the fundamental issue, and basic causes, which are more immediate but not necessarily the source of the problem.

💡Human Error

Human error is a significant factor in accident causation, often resulting from unsafe acts or conditions. The script discusses the shift in safety management from engineering to managing human behavior to prevent such errors, emphasizing the role of understanding human behavior in workplace safety.

💡Maslow's Hierarchy of Needs

Abraham Maslow's Hierarchy of Needs is mentioned in the script as a model for understanding human motivation. It suggests that individuals are motivated by a hierarchy of needs, from basic physiological needs to self-actualization. The script implies that addressing these needs can contribute to a safer workplace by influencing worker behavior.

💡Iceberg Model

The iceberg model represents the costs of accidents, with direct costs being the visible tip and indirect costs, which are often much larger, hidden beneath the surface. The script uses this metaphor to illustrate that while direct costs like medical expenses are apparent, indirect costs such as lost productivity can have a more significant impact on a company.

💡Domino Theory

The domino theory, presented by Herbert W Heinrich, suggests that accidents result from a chain of sequential events, similar to a line of dominoes falling. The script uses this theory to explain how removing one link in the chain, typically an unsafe act, can prevent an accident from occurring.

💡Prevention Program

A prevention program refers to a set of measures and strategies designed to prevent accidents and incidents. The script emphasizes the importance of such programs in workplaces, suggesting that a combination of theories and models can be effective in addressing the various factors that contribute to accidents.

Highlights

The presentation discusses theories and models developed by safety experts to understand how accidents happen and prevent them.

Accident prevention programs aim to prevent unsafe acts and conditions, which are foundational to safety.

Understanding the classification of accidents and incidents is crucial for effective prevention strategies.

The accident triangle ratio, introduced by Heinrich, suggests a relationship between near-misses, minor injuries, and major injuries.

Unsafe acts and conditions are identified as primary causes of workplace accidents.

The concept of near-misses, or incidents with potential for injury but no actual harm, is explored.

Property damage and lost time injury (LTI) are discussed as consequences of accidents in the workplace.

The domino theory by Heinrich explains accidents as a chain of sequential events, emphasizing the prevention of unsafe acts.

Frank E Bird's amended accident triangle shows a different ratio, focusing on property damage and incidents without injury.

Human error in accident causation has become a significant area of study, with human behavior models like Maslow's Hierarchy of Needs being applied.

The iceberg model illustrates the direct and indirect costs of workplace accidents, highlighting the financial impact.

Single factor theory and multiple factors theory are compared in terms of their effectiveness in accident prevention.

Root cause analysis is defined and its importance in preventing accident recurrence is emphasized.

The presentation concludes with a call to action for developing effective workplace accident prevention programs.

A combination of theories and models may provide a better approach to solving safety problems in the workplace.

The importance of understanding the difference between root cause and basic cause of an accident is discussed for effective investigation.

Transcripts

Hello and welcome, my name is Azman Abdul  Rahman. In this presentation we look at some  

of the theories and models that were developed  by safety expert to help better understanding  

on how accidents happen. This theories provided  the foundation for accident prevention program  

aimed at preventing accident, by preventing  unsafe acts and unsafe conditions. 

By the end of this presentation  you should be able to understand  

how accident and incident are classified;  what are the accident triangle ratio of  

different types of accident; what  are the cause involved in accident;  

the theory of accident causation a theory that  explains how accident happens; and the last one  

is root cause analysis, it helps to understand  difference between root cause and basic cause  

of an accident. All of these theories are very  useful when conducting accident investigation.  

You can also apply these theories to your  workplace accident prevention program.  

A combination of theories and model may be  the better approach towards problem solution. 

Accident and incident are the two  words that are easy to confuse  

but they are not exactly the same. Let's begin by  defining exactly what accident and incident is.  

Accident can be defined as an unplanned and  unexpected event that cause loss of life  

injury property damage interruption of  normal activities or damage to environment.  

Incident is unplanned and unexpected  event that has potential to cause injury,  

illness or property damage, sometimes they are  called near-miss. So both events are unplanned,  

both can present injury or damage, the difference  is in accident the event results in injury,  

however in incident the event does not but it has  potential to cause injury. Basically by definition  

all accidents begin with an incident but  not all incidents result in an accident.

In this example you will see the relationship  between incident and accident. Bricks  

and a hole in a walkway are hazard. Riding a  bicycle just beside the brick is an incident.  

Riding a bicycle in the  hole will cause an accident.  

Both are events, already happen. One has  no result and the other caused an accident.

There are several ways to classify an accident,  this includes classification by the extent  

of injury cause or by the level or  cause of the damage to property.

Unsafe acts are things that people  do that are obviously just not safe.  

Some examples are horseplay not using PPE,  using damage tools, violating safety rules.

Unsafe conditions are a condition in the workplace  that is likely to cause injury or property damage,  

such as missing machine guards, damage equipment,  slippery floor and improper storage of material.

A near-miss is any form of incident  that has the potential to cause  

but does not actually result in injury or property  damage or any interruption to normal operation.  

Near misses also may be referred  to as close call or near accident.

Property damage is damage or destruction of  real or personal property caused by negligence,  

willful destruction or act of nature.

Accident is any unplanned or unexpected  event which causes injury or property damage.  

Accident may involve lost time injury or  

LTI, simply means that number of days the workers  cannot work due to the injury. LTI also includes  

number of days the workers unable to perform  his or her normal duties after returned to work.

Accident triangle shows a relationship between the  number of accidents resulting in serious injury,  

minor injuries or no injuries. The relationship  was first introduced in 1931 by Herbert William  

Heinrich. Heinrich was a pioneer in the  field of workplace safety and health.  

From the study of 75 000 accident reports data  he suggested for every 300 near misses there  

will be 29 minor injuries and one major injury.  He concluded that by reducing the number of  

minor accidents companies will see a  fall in the number of major accidents.  

The triangle was widely used in the  industrial safety and health program  

and was described as a foundation  of safety and health philosophy.

The theory was developed further by Frank E Bird  in 1966 based on the analysis of 1.7 million  

accident reports. He produced an amended  triangle that showed a relationship of  

one serious injury accident to 10 minor  injury accidents to 30 property damage  

caused by accidents to 600 incident or  near-misses without injury. Bird shows a  

relationship between the number of reported  incident and the number of major accidents,  

and claimed that the majority of accident  could be prevented by taking proper control.

Whenever an accident occurs someone always asks  how did it happen ? Accident do not just happen,  

they are caused. Causes of accident can be unsafe  act, unsafe condition or a combination of both.  

If you are going to prevent accident we must know  what causes the unsafe act and unsafe condition.

Studies by Heinrich shows that 88% of  all accidents are caused by unsafe action  

or unsafe practices, such as reaching into a  running machine, operating a machine without  

guards, using defective tools or equipment,  or horseplay during work. 10% are caused  

by unsafe condition such as poor housekeeping,  improper storage, defective or broken equipment,  

machine with no guards and so on. However  unsafe condition exists as a result of personal  

action of a person. And only two percent are  caused by uncontrolled factors or act of nature.

Over the period of time safety  management approach has shifted from  

engineering to managing human to prevent  human error. Recently a lot of study has  

been conducted about the role of  human error in accident causation. 

Study of human behavior has become important  aspect in managing safety at workplace. One of  

the good model for understanding what motivates  human is Abraham Maslow's Hierarchy of Needs.  

Maslow first introduced this concept in 1943. This  theory explained that people are motivated by five  

basic categories of needs; they are physiological  security belonging esteem and self-actualization.  

Needs lower down in the hierarchy  must be satisfied before  

individuals can attend to the higher needs.

Accidents do not just happen, they are caused.  

Accidents do not have single cause. The accidents  are usually the result of a combination of factors  

which may vary from situation to situation.  There is a lot of possibilities for what  

can contribute or cause a workplace  injury. They can be grouped into four,  

that is environment, equipment and materials,  system and procedure or error of worker.

Employers should aware of these contributing  factors that may exist in their workplace.  

Equipment, are equipment and  tools suitable for the task,  

are substances used in the workplace being  handled stored and disposed of properly.  

System and procedure, are  their safe operating procedure,  

are there any rules and force, are instruction  and training provided for each workers.  

Environment, does the work environment  such as facility layout, walking surfaces,  

ventilation, lighting create any hazard, are  they comply with local environmental law.  

Worker, are they trained and skilled in  performing the work, what are the workers  

attitudes towards their work, are they focused  when doing their work, are they overtired.

Any accident at work result in both direct and  

indirect costs which are represented by  the iceberg model. Direct caused tend  

to be the one that we think off first, they  include medical costs and wage replacement.  

Indirect costs are hidden costs, they account for  more of the overall cost of an accident. They can  

be 8 to 36 times higher than direct cost depending  on various factors following the accident.  

Indirect injury costs include but are not limited  to legal cost, repair or replacement of damaged  

materials or equipment, product delay, loss of  future business and so on. All this causes can  

have an impact on company business. By avoiding  accident, company can save money and time.  

You can estimate the magnitude of the accident  by comparing the number of accidents with the  

lost work days. You should also include in your  report any course incurred during the accident

For decades people been asking this question :  why do accidents happen ? Over the years several  

theories of accident causation were introduced  that tried to explain why accidents occur.  

Single factor theory assumed that an accident  is the result of single course. Further, if that  

single course can be identified and eliminated the  incident will not be repeated. The reality is that  

accidents always have more than one contributing  factors. The multiple factors theory says that  

an accident occurs when a number of factors act  together cause an accident. Determining the cause  

leading to an accident can be quite difficult as  there are so many factors to consider. An accident  

causation model is a systematic method of finding  what type of failure or area cause accident  

and so action can be taken to address this  failure, before they have the chance to occur.

This example shows a comparison between single  and multiple model of accident causation.  

In this scenario a forklift accidentally  hit a worker while walking at a warehouse.  

According to the single model the only cause is  forklift operator fault for not being careful,  

the solution is to take a disciplinary action.  

When using the multiple model several causes  of accident can be identified, among them are  

does the forklift operator properly trained  on operating the forklift, does the operator  

authorize to operate the forklift, is there any  safe operating procedure for operating a forklift,  

thus the forklift is in good condition and  safe to drive, does the environmental condition  

such as lighting or ventilation at the  warehouse create hazard, and so on.

In 1931 Herbert W Heinrich presented a model  known as the domino theory. This theory  

stated that the accident results from a chain of  sequential events, just like a line of dominoes  

falling over. When one of the dominoes falls it  triggers the next one and the next one and so on.  

The sequence is, injury such as  cut, fracture. Injury is caused by  

accident, the event that results in injury  due to the unsafe act or unsafe condition,  

due to the fault of the person that is  negative traits that lead to unsafe acts,  

caused by their negative traits that inherited  from social environment. According to Heinrich  

the accident is avoided by removing one of the  dominoes normally the middle one or unsafe acts.  

This theory provided foundation  for accident prevention  

measure aim at preventing  unsafe act and unsafe condition.

The first update of the domino theory  was presented by Bird and Loftus in 1976.  

Using the same number of domino the elements  are lack of control, refers to inadequate system  

standard and compliance by the management,  this lead to the basic courses that includes  

human factors such as incompetent, and also  job factor such as inadequate work standard.  

Immediate causes are unsafe act and unsafe  condition, they are symptoms of incident.

Accident is undesired events such as contact with  hazardous substances, contact with hot object. And  

loss is the result of accident, it can be  loss to human, property and environment.

Bird stated that management  failure is another leading cause  

of accident at work. Management should implement  

an effective safety and health program that  able to prevent accidents and avoid injury.

This example applied the bird domino model.  In this scenario a worker had an accident  

while operating a stamping machine.  Let's analyze each sequence of events.  

Worker hand caught between moving object while  trying to reach something in the machine,  

as the result the worker's hand crushed and  suffers from major injury. Why the worker's  

hand crashed? because the workers put his hand  inside the machine while it is in motion. How  

can the workers can enter dangerous part  of the machine? because the safety sensors  

that supposed to protect the workers is not  functioning. Why the sensor is not functioning?  

because there is no one assigned  to repair the machine safety sensor  

and the management did not perform  routine check of the machine safety.

For the control measures, the management  can control at the immediate courses that  

is remind the worker not to put his hand into the  machine, and at the same time put a warning sign.  

However this is not an effective control as the  worker may forget and repeating to the unsafe act.  

The best way is at the first domino  that is repair or replace the sensor  

and make sure it is functioning and tested daily  before letting the worker operate the machine.  

From here we can concluded that if the  safety sensor is repaired at the early stage  

that is controlled from the management, accident  will not happen and injury can be avoided.

Causes of accident can be classified into  three. The basic or root cause is the most  

fundamental cause that can be corrected to  prevent recurrence of the error, such as  

poor safety management rules not enforce lack of  training and so on, they are underlying causes.

Contributing causes are even or conditions that  increase probability or severity of the accident,  

such as equipment failure missing guard and  so on. Direct causes is an immediate event  

usually the result of one or more unsafe act or  unsafe condition such as ignoring safety rules,  

horseplay, and so on. They are the symptoms  showing signs of poor safety management system.

Corrective action that focusing only on  contributing and direct causes of an accident  

may eliminate the symptom of a problem, but  not the actual underlying problem itself.

This may lead to recurrence of similar  issue or problem in the future.

Root cause analysis is defined  as a systematic process for  

identifying the root causes of problem or event  and an action plan for responding to them.  

A root cause analysis answered these  questions : what happened? how did it happen?  

why it happened? and what need to be  corrected. By conducting a root cause  

analysis employer may be able to completely  prevent the same incident from recurring.

Following are the tools necessary to  conduct root cause analysis. Employers  

should use a combination of the  tools to get an optimum result.

This concludes my today's presentation.  I hope this will be useful in developing  

your workplace accident prevention  program. Thank you and see you again.