ENG-6201 Occupational Health and Safety

WEEK 3 – ACCIDENTS AND THEIR EFFECT ON

INDUSTRY
This course introduces the student to the study of workplace occupational health and safety.
The student will learn safe work practices in offices, industry and construction as well as how
to identify and prevent or correct problems associated with occupational safety and health in
these locations as well as in the home. The course is designed to assist the student with the
implementation of safe healthy practices at work and at home.

http://www.icdo.org/en/disasters/man-made-disasters/industrial-accidents/explosions/

Workplace Accidents: Common Causes and Consequences

Workplace accidents can be costly no matter how minor they may be. When safety
procedures are not followed and accidents occur, the financial impact to your organization
can be staggering. Workplace accidents are generally classified as either employee or
customer.

Some of the consequences of employee accidents include:

 Personal hardships [pain and suffering]

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 Loss of work
 Reduced productivity
 Poor employee morale
 Increased unnecessary costs to the organization [medical expenses, increased worker’s
compensations, and increased insurance premiums]

Some consequences associated with customer accidents include:

 Poor company reputation

 Decreased customer satisfaction
 Reduced repeat business and referrals
 Potential litigation.

Over 90% of workplace accidents are caused by unsafe acts or conditions. The most common
causes of injury to employees and customers include:

 Improper handling of objects [lifting, pushing, pulling, etc.]

 Falls [standing in chairs, wet floors, tripping over objects, poor housekeeping, etc.]
 Struck by falling objects [items from shelves, hangers on the wall, etc.]
 Running into objects [boxes, furniture, equipment, glass windows, etc.]
 Improper body movement [stooping, bending, twisting, etc.]
 Contact with electricity
In order to control accidents, you must be able to recognize unsafe acts and conditions and
understand the appropriate action needed to eliminate the hazard.

REFERENCES:
ONLINE REFERENCE:
1. http://oahumanresources.com/workplace-accidents-common-causes-and-consequences/

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 ENG-6201 Occupational Health and Safety
WEEK 4 – THEORIES OF ACCIDENTS
This course introduces the student to the study of workplace occupational health and safety.
The student will learn safe work practices in offices, industry and construction as well as how
to identify and prevent or correct problems associated with occupational safety and health in
these locations as well as in the home. The course is designed to assist the student with the
implementation of safe healthy practices at work and at home.

Heinrich’s Domino Model of Accident Causation

Herbert W. Heinrich was a pioneering occupational safety researcher, whose 1931

publication Industrial Accident Prevention: A Scientific Approach [Heinrich 1931] was based
on the analysis of large amounts of accident data collected by his employer, a large insurance
company. This work, which continued for more than thirty years, identified causal factors of
industrial accidents including “unsafe acts of people” and “unsafe mechanical or physical
conditions”.

Heinrich is most famous for originating the concept of the “safety pyramid”. He also
developed the “five domino model” of accident causation, a sequential accident
model which represents an accident sequence as a causal chain of events, represented as
dominos that topple in a chain reaction. The fall of the first domino leads to the fall of the
second, followed by the third, etc., A similar analogy was in use in geopolitical theory during
the Cold War, speculating that if one country “fell” to communism, then surrounding
countries might quickly follow. This domino theory was used by the US administration to
justify the need for American intervention in various parts of the world.

The domino model of accident causation, as depicted by H. Heinrich in the 1950 edition of his book Industrial
Accident Prevention: A Scientific Approach

Heinrich saw the occurrence of a “preventable injury” as the culmination of a series of events
that form a sequence, similar to a row of dominos placed so that the toppling of a first domino
knocks down the next, which makes the third fall down, and so on until the entire row is

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 toppled. If this series is interrupted by the elimination of even one of the several factors that
comprise it, the injury will not occur, as illustrated in the figure below:

Accident prevention by interrupting the accident sequence, from the 1950 edition of the book Industrial Accident
Prevention: A Scientific Approach

In the first version of this model, published in 1931, the five factors identified were:

 domino 1: ancestry and the worker’s social environment, which impact the worker’s skills,
beliefs and “traits of character”, Heinrich wrote that “Recklessness, stubbornness,
avariciousness, and other undesirable traits of character may be passed along through
inheritance”. This kind of belief is not very different from that held by supporters of eugenics.

 domino 2: the worker’s carelessness or personal faults, which lead them to pay insufficient
attention to the task (see box about “accident-proneness” theory)

 domino 3: an unsafe act or a mechanical/physical hazard, such as a worker error (standing

under suspended loads, starting machinery without warning…) or a technical equipment
failure or insufficiently protected machinery

 domino 4: the accident

 domino 5: injuries or loss, the consequences of the accident

“Accident-proneness” theory

During the period 1920–1960, a number of industrial psychologists put forward a theory
that certain workers are more “accident-prone” than others (they are more likely than others
to sustain accidents, even though exposed to equal risk) [Burnham 2008]. Some people
working in high-risk industries still hold this belief. However, research since the 1960s

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 shows that this theory has little validity. Some population categories do tend to have more
accidents than others (for instance, young male drivers tend to have more car accidents than
older — more experienced — drivers), but these factors concern a category of people (age,
level of experience, level of education, for example) rather than a specific individual.

Organizational and workplace factors have a greater impact on the occurrence of accidents
than factors related to the individual. Finally, any theory concerning accidents that leads to
the allocation of blame on individuals has many negative side-effects for safety, such as
encouraging defensive reactions by individuals that strongly reduce the reporting and
sharing of safety information. For these reasons, “accident-proneness” theory is not a useful
concept for safety management.

Over time, the idea of attributing workplace behavior to ancestry and to ingrained personal
faults was found to be inappropriate, and more recent versions of the model replace the
labelling of the first two dominos by aspects related to planning, work organization and
leadership, or more generally management’s control of organizational factors of safety.

This theory of accident causation was later further developed by Frank Bird, who improved
the description of managerial “dominos”, and who generalized the last “accident” domino to
cover any loss (lost production, damage to equipment or other assets, and not only injuries).

Interpretation

This linear accident model is simple and easy to understand. Compared with the very
simplistic analyses that were common at the time (“accident caused by worker error”), it
helped managers to think about and identify underlying causal factors that could contribute
to accidents. Its promise of allowing the interruption of the accident sequence by acting on
underlying causal factors (“pulling out a domino”) helps to convince people to adopt the
corrective actions suggested by the accident investigation.

However, the model can contribute to a focus on the search for culprits or people to blame
in the accident sequence, rather than on a detailed understanding of all the factors that may
have contributed to the accident.

Criticism

The domino model is widely seen today as being too simplistic to be a useful tool to help
understand the causal factors of accidents:

 It leads to an excessively simple view of the contribution of human performance to accidents,

and to a focus on training and procedural compliance (including “behavior-based safety”
programs), rather than on system design, workload and incentives.

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 It adopts a purely linear and mechanical model of causality, which is inappropriate in
complex systems where accidents are generally caused by many interacting, partially
competing and unpredictable factors.

REFERENCES:
ONLINE REFERENCE:
1. https://risk-engineering.org/concept/Heinrich-dominos
2. Burnham, John C. 2008. “The syndrome of accident proneness (Unfallneigung): Why
psychiatrists did not adopt and medicalize it.” History of Psychiatry 19 (3): 251–
74. DOIDOI10.1177/0957154X0707759410.1177/0957154X07077594
3. Heinrich, Herbert William. 1931. Industrial accident prevention: A scientific approach. New
York. McGraw-Hill.

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 ENG-6201 Occupational Health and Safety
WEEK 4 – THEORIES OF ACCIDENTS
This course introduces the student to the study of workplace occupational health and safety.
The student will learn safe work practices in offices, industry and construction as well as how
to identify and prevent or correct problems associated with occupational safety and health in
these locations as well as in the home. The course is designed to assist the student with the
implementation of safe healthy practices at work and at home.

Lecture Notes

Key points that should be made in this lecture are as follows:

 The Domino Theory of Accident Causation was one of the earliest developed. The
theory posits that injuries result from a series of factors, one of which is an accident.
The theory is operationalized in ten statements called the Axioms of Industrial Safety.
According to this theory, there are five factors in the sequence of events leading to an
accident: ancestry/social environment, fault of person, unsafe act/mechanical or
physical hazard, accident, and injury.
 The Human Factors Theory of Accident Causation attributes accidents to a chain
of events ultimately caused by human error. It consists of three broad factors that
lead to human error: overload, inappropriate response, and inappropriate activities.
 The Accident/Incident Theory of Accident Causation is an extension of the human
factors theory. It introduces such new elements as ergonomic traps, the decision to
err, and systems failures.
 The Epidemiological Theory of Accident Causation holds that the models used for
studying and determining the relationships between environmental factors and
disease can be used to study causal relationships between environmental factors and
accidents.
 The Systems Theory of Accident Causation views any situation in which an
accident might occur as a system with three components: person (host), machine
(agency), and environment.
 The Combination Theory of Accident Causation posits that no one model/theory
can explain all accidents. Factors from two or more models might be part of the cause.
 There are seven principles of behavior-based safety: intervention; identification;
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; and planned interventions.
 Drugs and Alcohol are the root or a contributing cause of many workplace accidents
every year. Approximately 77 percent of drug users are employed, and more than a
third of all workers between 18 and 25 are binge drinkers. Alcoholism alone causes
500 million lost days annually.

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  Clinical Depression is an invisible problem in the workplace. However, it can be a
major cause of accidents. One in 20 people suffer from clinical depression, which is
the root cause of more than 200 million lost workdays annually.
 Management Failures are another leading cause of accidents on the job. If
management is serious about workplace safety and health, it must establish
expectations, provide training, evaluate employee performance with safety in mind,
and reinforce safe and healthy behavior.
 There is a strong correlation between obesity and injuries, suggesting a need to
promote optimal body weight as an injury prevention strategy.

REFERENCES:
ONLINE REFERENCE:
1. http://wps.prenhall.com/chet_goetsch_occupation_7/139/35769/9157107.cw/-
/9157132/index.html