19.accident-causation pptx - د. سهيلة

ACCIDENT CAUSATION

Early Man

Industrial Revolution

Factory managers reasoned that
workers were hurt because —
PEOPLE PROBLEM

ACCIDENT

Number is Up
People Error
Carelessness
Act of God
Cost of doing
Business

Domino Theory
1932 First Scientific Approach to
Accident/Prevention - H.W. Heinrich
“Industrial Accident Prevention”

Social Environment

and Ancestry

Fault of the

Person (Carelessness)

Unsafe Act

or
Condition

Accident

Injury

MISTAKES OF PEOPLE

Heinrich’s Theorems
INJURY - caused by accidents.
ACCIDENTS - caused by an unsafe act –injured person or an unsafe condition – work place.
UNSAFE ACTS/CONDITIONS - caused by careless persons or poorly designed or improperly maintained equipment.
FAULT OF PERSONS - created by social environment or acquired by ancestry.
SOCIAL ENVIRONMENT/ANCESTRY - where and how a person was raised and educated.

Heinrich’s Theory

Corrective Action Sequence (The three “E”s)
Engineering
Education
Enforcement

Human Factors Theory

Overload
Environmental Factors (noise, distractions
Internal Factors (personal problems, emotional stress)
Situational Factors (unclear instructions, risk level)

Inappropriate Response

Detecting a hazard but not correcting it
Removing safeguards from machines and equipment
Ignoring safety
Inappropriate Activities
Performing tasks without the requisite training
Misjudging the degree of risk involved with a given task

Petersen’s Accident/IncidentTheory

Overload

Pressure
Fatigue
Motivation
Drugs
Alcohol
Worry

Ergonomic Traps

Incompatible workstation (i.e. size, force, reach, feel)
Incompatible expectations
Decision to Err
Misjudgment of the risk
Unconscious desire to err
Logical decision based on the situation

Systems Failure

Policy Inspection
Responsibility Correction
Training Standards

Human Error
Accident
Injury/Damage

Epidemiological Theory

Predisposition Characteristics
Susceptibility of people
Perceptions
Environmental factors

Situational Characteristics

Risk assessment by individuals
Peer pressure
Priorities of the supervisor
Attitude

Can cause or prevent accident conditions

Systems Theory Model

Machine
Person
Environment
Interaction

Collect information

Weigh risks
Make
decision

Task to be performed

Combination Theory
For some accidents, a given model may be very accurate, for others less so
Often the cause of an accident cannot be adequately explained by just one model/theory
Actual cause may combine parts of several different models

Behavioral Theory

Often referred to as behavior-based safety (BBS)
7 basic principles of BBS
Intervention
Identification of internal factors
Motivation to behave in the desired manner
Focus on the positive consequences of appropriate behavior
Application of the scientific method
Integration of information
Planned interventions

Modern Causation Model

OPERATINGERROR

RESULT:

No damage
or injury

Many fatalities

Major damage

MISHAP (POSSIBLE)

Examples
Operating Errors:
Being in an unsafe position
Stacking supplies in unstable stacks
Poor housekeeping
Removing a guard

Systems Defect

Revolutionized accident prevention

A weakness in the design or operation of a system or program

Examples
Systems defects include:
Improper assignment of responsibility
Improper climate of motivation
Inadequate training and education
Inadequate equipment and supplies
Improper procedures for the selection & assignment of personnel
Improper allocation of funds

Modern Causation Model

OPERATINGERROR

RESULT:

No damage
or injury

Many fatalities

Major damage

MISHAP (POSSIBLE)

Operating Errors occur because
people make mistakes,
but more importantly,
they occur because of
SYSTEM DEFECTS

Modern Causation Model
Managers design the Systems
System defects occur because of

OPERATINGERRORS

RESULT:

No damage
or injury

Many fatalities

Major damage

MISHAP (POSSIBLE)

SYSTEM

DEFECTS

COMMAND ERROR

MANAGEMENT / COMMAND ERROR

Safety Program Defect

A defect in some aspect of the
safety program that
allows an avoidable error to exist.
Ineffective Information Collection
Weak Causation Analysis
Poor Countermeasures
Inadequate Implementation Procedures
Inadequate Control

Safety Management Error
A weakness in the knowledge or motivation
of the safety manager that
permits a preventable defect in
the safety program to exist.

SAFETY

MANAGEMENT
ERROR

Modern Causation Model

SAFETY
MANAGEMENT
ERROR

SAFETY
PROGRAM
DEFECT

COMMAND

ERROR

SYSTEM

DEFECT

OPERATING

ERROR

MISHAP

RESULTS

Near-Miss Relationship
Initial studies show for each disabling injury, there were 29 minor injuries and 300 close calls/no injury.
Recent studies indicate for each serious result there are 59 minor and 600 near-misses.
INITIAL STUDIES
RECENT STUDIES

1
SERIOUS
MINOR
CLOSE CALL

29
300

1
SERIOUS
MINOR
CLOSE CALL

59
600

Iceberg Principle

Outcomes (Consequences)

Incident (Accident)

Causal Factor
Causal Factor
Causal Factor

Primary Causal Factor

Seven Avenues
There are seven avenues through which we can initiate countermeasures. They are:
Safety management error
Safety program defect
Management / Command error
System defect
Operating error
Mishap
Result