This document discusses accident prevention theory and risk management. It covers several accident causation theories including the domino theory, human factors theory, accident/incident theory, epidemiological theory, systems theory, and combination theory. The domino theory proposed by Heinrich in the 1930s views accidents as resulting from a chain of events beginning with social environment and ancestry factors. The human factors theory attributes accidents to overload, inappropriate responses, and inappropriate activities leading to human error. The accident/incident theory extends this by including ergonomic traps and decisions to err. Risk assessment and management are also described as important aspects of accident prevention.

1. ACCIDENT PREVENTION THEORY &
RISK MANAGEMENT
Dr yinka ADENIRAN

2. LEARNING OBJECTIVES
• DISCUSS ACCIDENTS CAUSATION THEORIES
• DISCUSS ACCIDENT PREVENTION
• DESCRIBE/DISCUSS RISK ASSESSMENT &
MANAGEMENT

3. INTRODUCTION
Industrial work place accidents
• 3/100 persons per year
• One accidental death every 51 minutes
• One injury every 19 seconds

4. OCCUPATIONAL ACCIDENT
A sudden and unexpected event or series
of events occur or occurs when work is
performed that results in something
injurious causing injury or damage to
people, materials, processes, etc.

5. RELATED CONCEPTS
The near miss
”A sudden and unexpected event or series of events that contains or
contain something that can cause injury or damage, but due to
fortuitous circumstances does not have injurious consequences”.
Dangerous situations and dangerous actions
” Situations or actions that have the potential for the occurrence of
sudden and unexpected events, which contain a source of danger
that can cause injury or damage”.

6. WHY DO ACCIDENTS HAPPEN?

7. WHY DO ACCIDENTS HAPPEN?
• Is there a theory that explains the causes of
accidents?
• To prevent accidents we need to know the causes.
• Six widely used theories for accident causation

8. Factory managers reasoned that
workers were hurt because —
ACCIDENT
PEOPLE PROBLEM
Industrial Revolution
Number is Up
People ErrorCarelessness
Act of God
Cost of doing
Business

9. THEORIES OF ACCIDENTS CAUSATION
• Domino Theory
• Human FactorsTheory
• Accident / IncidentTheory
• Epidemiological Theory
• SystemsTheory
• CombinationTheory

10. “Industrial Accident Prevention”
1932 First Scientific Approach to
Accident/Prevention - H.W. Heinrich.
Domino Theory
Social
Environment
and Ancestry
Fault of the
Person
(Carelessness)
Unsafe Act
or
Physical hazard
Accident Injury
MISTAKES OF PEOPLE

11. HEINRICH’S THEOREMS
• INJURY - caused by accidents.
• ACCIDENTS - caused by an unsafe act –
injured person or an unsafe condition –
work place.
• UNSAFE ACTS/PHYSICAL HAZARD - caused by
careless persons or poorly designed or
improperly maintained equipment ETC
• FAULT OF PERSONS - created by social
environment or acquired by ancestry.
• SOCIAL ENVIRONMENT/ANCESTRY - where and
how a person was raised and educated.

12. HEINRICH’S AXIOMS OF INDUSTRIAL
SAFETY
1. Injuries result from a series of preceding factors.
2. Accidents occur as the result of physical hazard or an unsafe act.
3. Most accidents are the result of unsafe behavior.
4. Unsafe acts and hazards do not always result in immediate
accidents and injuries.
5. Understanding why people commit unsafe acts helps to establish
guidelines for corrective actions.

13. HEINRICH’S AXIOMS OF INDUSTRIAL
SAFETY
6.The severity of the injury is largely fortuitous
and the accident that caused it is preventable.
7. Best accident prevention techniques are analogous to best quality /
productivity techniques.
8. Management should assume safety responsibilities.
9. The supervisor is the key person in the prevention of industrial
accidents.
10. Cost of accidents include both direct costs and indirect costs.

14. HUMAN FACTORS THEORY
Chain of events ultimately caused
by human error
Three factors
• Overload
• Inappropriate response
• Inappropriate activities

15. HUMAN FACTORS THEORY
Overload
• Capacity - abilities
• Load
• Environmental factors (e.g noise)
• Internal factors (e.g. personal problems)
• Situational factors (e.g. risk)

16. HUMAN FACTORS THEORY
Inappropriate response
• Ignores a suspected hazard
• Disregards established safety procedures
• Circumvents safety devices
• Includes incompatibility with person’s workstation
Size, Required Force, Reach, Feel, etc

17. HUMAN FACTORS THEORY
Inappropriate activities
• Doing a task without training
• Misjudging the degree of risk

18. ACCIDENT/INCIDENT THEORY
Human factors theory plus
• Ergonomic traps
• Decision to err
• System’s failure
• Overload + Ergonomic traps + Decision to err lead
to human error

19. 19
PETERSEN’S
Overload
SystemFailure
Injury / Damage
Accident
Human Error
Ergonomic Traps Decsion to Err
Accident / Incident Theory

20. OVERLOAD
• Pressures
• Deadlines, Budget Factors, Peer Pressure
• Fatigue
• Motivation
• Drugs
• Alcohol
• Worry

21. ERGONOMIC TRAPS
• Incompatible Workstation
• Incompatible Expectations

22. DECISION TO ERR
• Misjudgment of Risks
• Unconscious Desire to Err
• Logical Decision Based on Situation / Circumstances
• Superman Syndrome (It won’t happen to me!)
• - Bulletproof, Invincible, Immortal, Lucky

23. SYSTEM FAILURES
• Potential for causal relationship between
managerial decisions/behaviors regarding safety
• Policies
• Responsibilities
• Training
• Inspections
• Corrective Actions
• Standards

24. EPIDEMIOLOGICAL THEORY
• Causal relationship between environmental factors
and disease
• Extended to accidents
• Study causal relationships between environmental
factors and the accident

25. 25
EPIDEMIOLOGICAL THEORY
Can cause or prevent accident conditions
Predispositional
Characteristics
Situational
Characteristics
Epidemiological Theory

26. SYSTEMS THEORY
• System - interacting components intended to meet a
common goal. A change in any component affects the
entire system
• Components
• Person
• Machine
• Environment
• Collect information, weigh risks, make
decisions

27. FIRENZIE’S SYSTEMS THEORY
Person/Machine/Environment
• Information Gathering
• Risks Assessment
• Decision Making
• Task Performance
• Stressors can cloud the judgment during information gathering, risk
weighing, decision making processes.
Stressors

28. FIRENZIE’S RECOMMENDATIONS
Consider Five Factors -
before beginning the process of information
gathering, risk weighing, decision making.
• Job Requirements
• Worker’s Abilities and Limitations
• Gain from SuccessfulTask Completion
• Loss if Task Attempted but Results in Failure
• Loss if Task is Not Attempted

29. COMBINATION THEORY
• In many cases, one theory is not sufficient
• Need to use several models to explore the causes
of accidents
• Don’t rely on one theory

30. ACCIDENTS PREVENTION
It is impossible to remove and minimise all risks. Accident
risks will always be present where people travel, act, work,
develop and live.
Accident prevention is not about achieving ZERO risk, but
rather about achieving ZERO accidents

31. ACCIDENT PREVENTION
•DISCUSS

33. RISK ASSESSMENT

35. QUIZ
HerbertW. Heinrich's study of the causes of industrial accidents in
the 1920s concluded that most accidents are caused by:
Unsafe acts committed by fellow workers
Poor management
Lack of health and safety programs
Faulty machines and equipment

36. QUIZ
Carelessness, training, and management
Carelessness, overload, and training
Pressure, motivation, and fatigue
Overload, inappropriate response, and inappropriate activities
Which three factors lead to human error in
the human factors theory?
The systems theory views a situation in which an accident
might occur as a system comprised of:
Person, machine, and motivation
Motivation, peer pressure, and overload
Person, machine, and environment
Attitude, risk, and motivation

37. T/F
• Why accidents happen is a concern for health and safety decision-
makers
• Theories of accident causation are used to predict and prevent
accidents.
• The domino theory of accident causation was one of the earliest
theories developed.
• According to Heinrich's Axioms on Industrial Safety, the plant manager is
the key person concerning industrial accidents
• The human factors theory of accident causation attributes accidents to
a chain of events caused by human error
• An accident program does not have to take all ten axioms into account
to be effective
• The accident/incident theory is an extension of the human factors
theory.

38. ANSWER THE QUIZ
https://www.onlinequizcreator.com/accident-theories/quiz-261169

39. ESSAY QUESTIONS
• Discuss the domino theory of accident causation.
• Compare the human factors theory of accident
causation and the accident/incident theory of
accident causation.
• Discuss your opinion on how accidents are caused.
• Explain the concept of the epidemiological theory
of accident causation.

40. QUESTIONS