theory accident - osha

8/13/2019 THEORY ACCIDENT - OSHA

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Chapter 3

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CHAPTER 3ACCIDENTCAUSATION THEORIES

CEE 698Construction Health and Safety


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Chapter 3

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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 varioustrades working on a job site

Accidents should not be viewed as inevitable justbecause 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 theoryCombination theory

Behavioral theory

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Domino Theory

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Herbert W. HeinrichTravelers Insurance

Company

In the late 1920s, 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theory as outdated however todays more


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Axioms of Workplace Safety

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Conclusions laid foundation forAxioms ofIndustrial Safety(came to be known as theDomino 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 accidentthat caused it is largely preventable.


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Axioms of Workplace Safety

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7. The best accident prevention techniques are analogous with thebest quality and productivity standards.

8. Management should assume responsibility for safety because itis 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 arealso hidden or indirect costs.

Heinrich believed any safety programs taking all10 axioms into consideration will likely beeffective.


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Domino Theory

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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 whyhazardous conditions exist.

3. Unsafe acts and mechanical or physical hazards. Unsafe actscommitted by people and mechanical or physical hazards are thedirect 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

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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 andthe 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 injuriesCEE 698Construction Health and Safety


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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 dueto the nature of injuries. Therefore it was probably

inevitable to suffer from more serious injuries.

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Solution:

Removing the causal factor - the failure of warehouse personnel to use

their personal protective gear during summer months.

Forming a committee.

Committees 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.

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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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Capacityproduct of such factors as apersons natural ability, training, state of mind,fatigue, stress, and physical condition.

Loadconsisting of tasks for which a personis responsible and added burdens resultingfrom environmental factors (noise, heat),internal factors (personal problems, stress), andsituational factors (unclear instructions).

Statethe product of a persons motivationallevels.

Overload an imbalance between a personscapacity 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 persons workstation

with regard to size, force, reach, feel and

similar factors can lead to accidents andCEE 698Construction 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 thatmisjudgment.

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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 companys work force.

New teams of cabinet makers and installers

hired.

Authorized unlimited overtime.

Numbers of accidents and injuries

increased.

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Human Factors Theory -

Example Investigation revealed human errors in the

three categories:

Overload:

Employees working beyond their personal limits and beyondtheir 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

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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

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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 safetyare 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

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Accident / Incident Theory -

ExamplePanhandle 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 698Construction 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 CharacteristicsCEE 698Construction Health and Safety


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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 andmandatory 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.

Predis osition factor: Her susce tibilit to ressureCEE 698



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Systems Theory

Systema group of regularly interacting and interrelatedcomponents 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 howthese components interact.

Example: A worker who temporarily replaces an experiencedcrane operator increases the probability of an accident.

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Systems Theory

The primary components of the systems model arethe person, machine, environment, and information;decisions; risks; and the task to be performed.

Each of these components has a bearing on theprobability that an accident will occur.

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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

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Systems Theory - Example

Construction Service Company (CSC) makes customized trussesfor residential construction jobs.

Workers including the apprentices use manually operatedmachines 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 getscareless 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.

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Combination Theory

Often the cause of an accident cannot be

adequately described by one theory.

Differences between the theory and realitymay exist.

Combination theory helps explain the actual

cause of an accident by combining different

parts of several theories.

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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.

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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 tryingto 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 safetyprocedures

A faulty buckling mechanism on the safety harness

An unsafe design (only a knee-high guardrail on the catwalk)

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Behavioral Theory

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Referred to as Behavior-based safety(BBS)

E. Scott GellerSafety Performance

Solutions, Inc., and professor ofpsychology

Believes in 7 basic principles of BBS:

1. Use intervention that is focused on employeebehavior.

2. Identify external factors that aid in understandingand improving employee behavior.


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Behavioral Theory

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3. Direct behavior with activator or events antecedent tothe desired behavior, and motivate employees to

behave as desired with incentives and rewards thatfollow 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 tolimit possibilities.

7. Plan interventions with the feelings and attitudes ofthe individual employee in mind.


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BBS and ABC Model

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Behavior-based safety trainers and consultantsteach the ABC model (or three-termcontingency) as a framework to understand and

analyze behavior or to develop interventionsfor improving behavior. As given in BBSprinciple 3theAstands for activatorsorantecedent events that precede behavior (B),

andCrefers to the consequencesfollowingbehavior or produced by it. Activators directbehavior, whereas consequences motivatebehavior.


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BBS and ABCO Model

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Outcomerefers to the longer-term results of engagingin safe or unsafe behavior. For example, anantecedent of a sign requiring employees to wearsafety goggles could produce the behavior of putting

on the goggles, the consequence of avoiding an eyeinjury, and the outcome of being able to continueworking and enjoying time with the family. One theother hand, the consequence of not wearing goggles

could be an eye injury with a potential outcome ofblindness, time off the job, and a reduced quality oflife. Failure to address the issue of outcomesrepresents a lost opportunity to give employees agood 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 inwhich 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

j i f il ti ith h f ilCEE 698 Construction Health and Safety

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