1.AccidentTheories.ppt P36.ppt for safety

Safety measures

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Accidents in Construction
CEE 698 – Construction Health and Safety
Why do accidents happen in construction?
–Physical hazards
–Environmental hazards
–Human factors
–No safety regulations or poor ones
–Poor communication within, between, and among various
trades working on a job site
Accidents should not be viewed as inevitable just
because hazards exist.
For every accident that occurs, there is a cause.

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Theories of Accident Causation
The most widely known theories of
accident causation:
–Domino theory
–Human factors theory
–Accident / incident theory
–Epidemiological theory
–Systems theory
–Combination theory
–Behavioral theory
CEE 698 – Construction Health and Safety

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Domino Theory
CEE 698 – Construction Health and Safety
Herbert W. Heinrich – Traveler’s Insurance Company
In the late 1920’s, studying reports of 75,000
workplace accidents, he concluded the following:
–88% of accidents are caused by unsafe acts committed by fellow
workers
–10% of accidents are caused by unsafe conditions
–2% of accidents are unavoidable
Contemporary research considers domino theory as
outdated however today’s more widely accepted
theories can be traced back to Heinrich’s study.

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Axioms of Workplace Safety
CEE 698 – Construction Health and Safety
Conclusions laid foundation for Axioms of
Industrial Safety (came to be known as the Domino
Theory)
1.Injuries result from a completed series of factors, one of which is
the accident itself.
2.An accident can occur only as the result of an unsafe act by a
person or a physical or mechanical hazard, or both.
3.Most accidents are the result of unsafe behavior by people.
4.An unsafe act by a person or an unsafe condition does not always
immediately result in an accident or injury.
5.The reasons why people commit unsafe acts can serve as helpful
guides in selecting corrective actions.
6.The severity of an accident is largely fortuitous, and the accident
that caused it is largely preventable.

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Axioms of Workplace Safety
CEE 698 – Construction Health and Safety
7.The best accident prevention techniques are analogous with the
best quality and productivity standards.
8.Management should assume responsibility for safety because it
is in the best position to get results.
9.The supervisor is the key person in the prevention of workplace
accidents.
10.In addition to the direct costs of an accident (i.e., compensation,
liability claims, medical costs, and hospital expenses), there are
also hidden or indirect costs.
Heinrich believed any safety programs taking all
10 axioms into consideration will likely be
effective.

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Domino Theory
CEE 698 – Construction Health and Safety
Five factors in sequence leading to an accident:
1.Ancestry and social environment. Negative character traits that
may lead people to behave in an unsafe manner can be inherited
(ancestry) or acquired as a result of the social environment.
2.Fault of person. Negative character traits, whether inherited or
acquired, are why people behave in an unsafe manner and why
hazardous conditions exist.
3.Unsafe acts and mechanical or physical hazards. Unsafe acts
committed by people and mechanical or physical hazards are the
direct causes of accidents.
4.Accident. Typically, accidents that result in injury are caused by
falling or being hit by moving objects.
5.Injury. Typical injuries resulting from accidents include
lacerations and fractures.

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Domino Theory
CEE 698 – Construction Health and Safety
Two central points:
–Injuries are caused by preceding factors
–By removing the unsafe act or hazardous condition,
the action of these preceding factors is negated and
the accidents/injuries are prevented.

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Domino Theory - Example
Construction Products Company (CPC) is a
distributor of lumber, pipe and concrete products.
Warehouse personnel load most of the orders by
hand therefore they are required to wear personal
protective gear.
Management observed increases in minor injuries
among personnel during summer months.
However during the last summer they suffered
from the serious back injuries of two workers.
CEE 698 – Construction Health and Safety

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Domino Theory - Example
Investigation revealed a series of events and
a central causal behavior which created a
domino effect.
–Personal protective gear becomes uncomfortable
due to hot weather and loaders take it off.
–This situation increases the number of minor
injuries but management does not pay attention due
to the nature of injuries. Therefore it was probably
inevitable to suffer from more serious injuries.
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Domino Theory - Example
Solution:
–Removing the causal factor - the failure of warehouse personnel to use
their personal protective gear during summer months.
–Forming a committee.
–Committee’s recommendations:
1.Provide all warehouse personnel with training on the importance and
proper use of personal protection
2.Require warehouse supervisors to monitor the use of personal protection
gear more closely
3.Establish a company policy that contains specific and progressive
disciplinary measures for failure to use required personal protection gear
4.Implement several heat reduction measures to make warehouses cooler.
CEE 698 – Construction Health and Safety

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Human Factors Theory
Attributes accidents to a chain of events
ultimately caused by human error.
Consists of three broad factors that lead to
human error:
–Overload
–Inappropriate Response
–Inappropriate Activities
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Overload
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Capacity – product of such factors as a person’s
natural ability, training, state of mind, fatigue, stress,
and physical condition.
Load – consisting of tasks for which a person is
responsible and added burdens resulting from
environmental factors (noise, heat), internal factors
(personal problems, stress), and situational factors
(unclear instructions).
State – the product of a person’s motivational levels.
Overload – an imbalance between a person’s
capacity at a any given time and the load that the
person is carrying in a given state.

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Inappropriate Response or
Incompatibility
How a person responds to a given situation
can cause or prevent an accident.
Inappropriate response occurs when:
–A person detects a hazardous condition but does
nothing to correct it
–A person disregards an established safety procedure.
Incompatibility of a person’s workstation with
regard to size, force, reach, feel and similar
factors can lead to accidents and injuries.
CEE 698 – Construction Health and Safety

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Inappropriate Activities
Human error can be result of inappropriate
activities.
Examples:
–Person who undertakes a task that he / she does not
know how to do.
–A person who misjudges the degree of risk
involved in a given task and proceeds on that
misjudgment.
CEE 698 – Construction Health and Safety

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Human Factors Theory
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Human Factors Theory -
Example
Jones Cabinets & Construction Company
sees rapid growth in sales which
overwhelmed company’s work force.
New teams of cabinet makers and installers
hired.
Authorized unlimited overtime.
Numbers of accidents and injuries
increased.
CEE 698 – Construction Health and Safety

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Human Factors Theory -
Example
Investigation revealed human errors in the
three categories:
–Overload:
•Employees working beyond their personal limits and beyond
their capabilities.
•Stress, insufficient training and fatigue
–Inappropriate response:
•Carpenters removing the safeguards to speed up construction.
–Inappropriate activities:
•Assigning employees to duties for which they are not fully
trained
CEE 698 – Construction Health and Safety

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Accident / Incident Theory
Extension of human factors theory
Developed by Dan Petersen
New elements:
–Ergonomic traps
–The decision to err
–Systems failures
CEE 698 – Construction Health and Safety

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Accident/Incident Theory
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Accident / Incident Theory
Some of the reasons why systems may fail:
1.Management does not establish a comprehensive safety
policy
2.Responsibility and authority with regard to safety are
not clearly defined
3.Safety procedures, such as measurement, inspection,
correction, and investigation, are ignored or given
insufficient attention.
4.Employees do not receive proper orientation
5.Employees are not given sufficient safety training
CEE 698 – Construction Health and Safety

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Accident / Incident Theory -
Example
Panhandle Precast Concrete has developed a well-
earned reputation as a “safe company”.
When the safety manager of the firm, Jack Bond,
was elected as the president of a statewide safety
organization, safety problems within the firm began.
Jack Bond neglected his duties at PPC.
Workers stopped following the safety precautions
once they realized he had stopped observing and
correcting them.
CEE 698 – Construction Health and Safety

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Epidemiological Theory
Epidemiology: Study of causal relationships
between environmental factors and disease.
Epidemiological theory holds that the models used
for studying and determining these relationships
can also be used to study casual relationships
between environmental factors and accidents.
Components:
–Predisposition Characteristics
–Situational Characteristics
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Epidemiological Theory
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Epidemiological Theory -
Example
Jane Andrews was the newest member of the loading unit for
Construction Products, Inc.
She had 2 days of training on proper lifting techniques before
beginning the work and mandatory use of back-support belts
Her supervisor and colleagues pressured to disregard the
proper lifting methods she learned in training.
She followed her supervisor and after 2 months had to
undergo major surgery to repair two ruptured disks.
Predisposition factor: Her susceptibility to pressure from her
coworkers and supervisor
Situational factors: Peer pressure and priorities of supervisor
CEE 698 – Construction Health and Safety

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Systems Theory
System – a group of regularly interacting and
interrelated components that together form a unified
whole.
An accident may occur as a system which is composed
of:
–Person
–Machine
–Environment
The likelihood of an accident to occur is determined by
how these components interact.
Example: A worker who temporarily replaces an
experienced crane operator increases the probability of
an accident.
CEE 698 – Construction Health and Safety

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Systems Theory
The primary components of the systems model are
the person, machine, environment, and information;
decisions; risks; and the task to be performed.
Each of these components has a bearing on the
probability that an accident will occur.
CEE 698 – Construction Health and Safety

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Systems Theory
Factors which should be considered before
collecting information, weighing risks and
making a decision:
–job requirements
–the workers’ abilities and limitations
–the gain if the task is successfully accomplished
–the loss if the task is attempted but fails
–the loss if the task is not attempted
CEE 698 – Construction Health and Safety

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Systems Theory - Example
Construction Service Company (CSC) makes customized
trusses for residential construction jobs.
Workers including the apprentices use manually operated
machines which causes two problems:
–It is difficult for even experienced workers to make clean accurate cuts
–Machines are so old that they frequently break down.
While working under a major contract, an apprentice gets
careless and runs his hand into the saw blade.
The person-machine-environment chain:
–Person involved was inexperienced.
–Machine involved was old and prone to breakdown
–The environment was stressful and pressure-packed.
CEE 698 – Construction Health and Safety

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Combination Theory
Often the cause of an accident cannot be
adequately described by one theory.
Differences between the theory and reality
may exist.
Combination theory helps explain the
actual cause of an accident by combining
different parts of several theories.
CEE 698 – Construction Health and Safety

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Combination Theory - Example
Crestview Construction Company (CCC)
maintains four large warehouses .
Ventilation of these warehouses are important and
the vent filters need to be changed periodically.
Changing the vents filter involves two potential
hazards:
–Unvented dust and fumes can make breathing difficult.
–Vents are located 110 feet above the ground level,
which can be accessed through a narrow cat walk that
has knee-high guardrails.
CEE 698 – Construction Health and Safety

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Combination Theory - Example
CCC has well defined rules which are strictly enforced.
However an employee fell from the catwalk while he was
trying to change one of the filter. His lifeline held him for 20
minutes. When he panicked and tried to pull himself up he
knocked the buckle of his safety harness open and fell to the
concrete floor, breaking his neck.
Critical factors:
–Absence of supervisor
–Inexperience of worker
–A conscious decision by the worker to disregard the safety
procedures
–A faulty buckling mechanism on the safety harness
–An unsafe design (only a knee-high guardrail on the catwalk)
CEE 698 – Construction Health and Safety

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Behavioral Theory
CEE 698 – Construction Health and Safety
Referred to as Behavior-based safety
(BBS)
E. Scott Geller – Safety Performance
Solutions, Inc., and professor of
psychology
–Believes in 7 basic principles of BBS:
1.Use intervention that is focused on employee
behavior.
2.Identify external factors that aid in understanding
and improving employee behavior.

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Behavioral Theory
CEE 698 – Construction Health and Safety
3.Direct behavior with activator or events antecedent to
the desired behavior, and motivate employees to
behave as desired with incentives and rewards that
follow desired behavior.
4.Focus on the positive consequences that result from
the desired behavior as a way to motivate employees.
5.Apply scientific method to improve attempts at
behavioral interventions.
6.Use theory to integrate information rather than to
limit possibilities.
7.Plan interventions with the feelings and attitudes of
the individual employee in mind.

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BBS and ABC Model
CEE 698 – Construction Health and Safety
Behavior-based safety trainers and consultants teach
the ABC model (or three-term contingency) as a
framework to understand and analyze behavior or
to develop interventions for improving behavior.
As given in BBS principle 3…the A stands for
activators or antecedent events that precede
behavior (B), and C refers to the consequences
following behavior or produced by it. Activators
direct behavior, whereas consequences motivate
behavior.

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BBS and ABCO Model
CEE 698 – Construction Health and Safety
Outcome refers to the longer-term results of engaging in safe
or unsafe behavior. For example, an antecedent of a sign
requiring employees to wear safety goggles could produce
the behavior of putting on the goggles, the consequence of
avoiding an eye injury, and the outcome of being able to
continue working and enjoying time with the family. One
the other hand, the consequence of not wearing goggles
could be an eye injury with a potential outcome of
blindness, time off the job, and a reduced quality of life.
Failure to address the issue of outcomes represents a lost
opportunity to give employees a good reason for engaging
in safe behaviors.

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Behavioral Theory - Example
Jack Coker decided to apply the ABC model in
turning the unsafe behavior pattern of the workers
(not wearing hard hats) in Bonded Builders, Inc.
1.He removed the old “Hard Hat Area” signs and replaced
them with newer, more noticeable signs.
2.He scheduled a brief seminar on head injuries in which he
told a story of two employees. One was in a hospital bed
surrounded by family members he did not even
recognize; the other was shown enjoying a family outing
with happy family members.
CEE 698 – Construction Health and Safety