Causes, Prevention of Workplace Accidents

3. Accidents and Their Causes (8 hrs)
3.1 Definition of Accident, Incident, Hazard, and Risk
3.2 Hazard identification, Hazard evaluation, and Hazard
Control
3.3 Software causes: Unsafe Act, Unsafe Behavior, Poor
Communication, Lack of Training, Low Level of
Education of the Workers, and Low Skill of Workers
3.4 Hardware causes: Unsafe Work Site, Improper Tools
and Equipment, and Improper Storage of Materials
3.5 Accidents at Construction Sites
3.6 Losses due to accidents

3.1 Definition of Accident, Incident, Hazard,
and Risk
Accident
• Accident can be defined as an unexpected or
unforeseen event which causes or likely to
cause an injury, fatality, or may also result in
property damage.
Incident
• Incident can be defined as “an occurrence or
event that interrupts normal procedure but
doesn't result in serious injury or illness but may
result in property damage.

3.1 Definition of Accident, Incident, Hazard,
and Risk
Hazard
• Hazard can be defined as “a potential to cause harm or injury”.
Risk
• Risk is the possibility of something bad happening in the
future.
• Risk is a situation that could be dangerous or have a bad
result i.e. occurrence of harm or injury and loss of property.
Near-miss
• Near-miss can be defined as “an incident which does not
result any injury, death or any other loss”

3.2 Hazard identification, Hazard evaluation,
and Hazard Control
Hazard identification
• Hazard can be defined as “a potential to cause harm
to people, property and the environment”.
• Hazard identification is a process to identify hazards
and risk factors that have the potential to cause
harm.
• The purpose of hazard identification is to find and
record possible hazards that may be present in
workplace.

and Hazard Control
Project team should inspect the work place by
• Looking at the physical work environment, equipment,
materials, products, etc. that are used.
• Looking how the tasks are done?
• Looking maintenance, repair, or cleaning.
• Talking to the workers: as they know their job and its
hazards best.

and Hazard Control
When should Hazard identification be done:
• During design (designing a new process/procedure).
• During implementation (purchasing and installing machinery)
• Before tasks are done.
• While tasks are being done (changes, abnormal conditions).
• During inspections by supervisor, and safety committee.
• After incidents.

and Hazard Control
Hazard evaluation
• Hazard can be classified as acute hazard and chronic
hazard.
• Acute hazard is defined as the potential for the injury or
damage to occur due to instantaneous or short duration
exposure to the undesirable events or conditions.
• Chronic hazard is defined as the potential for the injury
or damage to occur due to prolonged exposure to the
undesirable events or conditions.

and Hazard Control
Hazard evaluation
• Hazard evaluation is the analysis of a hazardous
situation or process of safety concern and help
identification of the unexpected events in
process or in operations.
• Both quantitative and qualitative methods are
practiced to analyze hazard evaluation in
construction.

and Hazard Control
Hazard evaluation requires:
• Management support.
• Trained competent people in hazard
evaluation.
• Adequate and up-to- date information and
drawings.
• Selection of the evaluation technique.

and Hazard Control
Hazard evaluation
Qualitative techniques: Identify potential accident
scenarios and evaluate tin sufficient detail to make a
reasonable judgment of risk.
Preliminary hazard analysis: Design review.
What-if analysis: A brainstorming approach in which
experienced people ask questions about possible
undesired events.

and Hazard Control
Hazard evaluation
Guide word analysis: Potential operating problems
are identified by asking what would happen if a step in
a procedure were skipped or performed incorrectly.
Operability analysis: Potential operating problems
are identified to investigate process deviation.
Quantitative techniques: Help in risk judgment by
providing more detailed, statistical evaluations of the
risk.

and Hazard Control
Hazard evaluation
Fault tree analysis: Identify failure by assigning
statistical values to calculate risk.
Human reliability analysis: Assign statistical values
of human actions to calculate the risk.
Hazard evaluation technique is more an art than a
science, there may be no “best” method for a particular
application.

and Hazard Control
Hazard control
Hazard control consists of all steps necessary to
protect workers from exposure to a workplace hazard.
Hazard control protect workers from
• Workplace hazards.
• Help to minimize injuries, illnesses and incidents.
• Minimize or eliminate safety and health risks.
• Help employers to prevent injuries or accidents in the
workplace.

and Hazard Control
Hazard control
• Identify and evaluate options for controlling
hazards using a "hierarchy of controls.”
• Use a hazard control plan to guide the selection
and implementation of hazard control.
• Evaluate effectiveness of existing hazard control.
• Review new technologies whether they are more
protective, more reliable, or less costly.

and Hazard Control
Hazard control method:
a. Evaluating and selecting temporary and
permanent control.
b. Implementing permanent (engineering) control
whenever practicable.
c. Implementing temporary measures until
permanent control can be put in place.

and Hazard Control
Hazard control process
a. Identify hazard control options - get input from
workers for simple hazard and consult with
expert for complex hazard.
b. Evaluate and select the control options - that are
most feasible, effective, and permanent.
c. Develop and update hazard control plan.

and Hazard Control
Hazard control process
d. Select hazard controls to protect workers
during nonroutine operations and
emergencies.
e. Implement selected controls in the workplace.
f. Follow up to confirm that controls are
effective.

and Hazard Control
Hazard control
• Implement hazard control measures according to the
priorities established in the hazard control plan
during hazard identification and assessment.
• Implement hazard control measures on a "worst-first"
basis according to risk ranking priorities.
• Employers have an obligation to protect workers from
recognized serious hazards.

3.3 Software causes: Unsafe act, Unsafe working
condition, Poor communication, Lack of training,
Low level of education of the workers, and Low skill
of the workers
Major causes of accidents are:
1. Unsafe act.
2. Unsafe working condition.
3. Environmental and personal factors.
• Accident statistics reveals that 60% of accidents occur due
to ‘unsafe acts’, 38% due to ‘unsafe working condition’, and
2% due to ‘environmental and personal factors’.

3.3 Software causes: Unsafe act
• The major part of the accidents are mainly
caused due to unsafe acts.
• Unsafe acts are due to the unsafe practices
committed by the workers because of lack of
knowledge or skills.
• Unsafe acts can be avoided by giving proper
education and training to line and low
management according to the concerned safe
work procedures.

Factors leading to unsafe acts are:
a. Lack of safety instructions.
b. Lack of proper communication.
c. Lack of effective supervision.
d. Lack of interest in job.
e. Lack of knowledge.
f. Inadequate job instructions.

Factors leading to unsafe acts are:
g. Ignorance on safety rules and practices.
h. Improper motivation.
i. Negligence towards safety.
j. Overconfidence.
k. Arson (burning) etc.

Some of the unsafe acts are:
a.Operating without authority.
b.Improperly using tools and equipment.
c. Working with defective tools and equipment.
d.Not wearing personal protective equipment.
e.Smoking in prohibited area.
f. Taking up unsafe position.
g.Unsafe manual lifting practices.
h.Violating safety rules and regulations.

Some of the unsafe acts are:
i. Discarding safety of others.
j. Negligence in use of safety appliances.
k. Working with defective personal protective equipment.
l. Operating machineries and equipment with extra
speed.
m.Horseplay.
n. Making safety devices inoperative.
o. Negative approach and temptation in conducting safe
work practices.

3.3 Software causes: Unsafe working condition
• Unsafe working condition can be avoided
by the contractor or management by taking
responsibility of maintaining safe working
condition adopting safe working procedure.
• Proper planning from the part of
management is necessary to constantly
maintain safe working environment.

Factors leading to unsafe conditions are:
a. Lack of safety awareness from the part of the
management.
b. Negative attitude of management personnel
towards safety.
c. Improper selection of key personnel.
d. Lack of proper safety inspection and audits.

Some unsafe working conditions are:
a.Defective equipment, machinery and tools.
b.Improper design or construction.
c. Improper plant layout.
d.Insufficient ‘light and ventilation’.
e.Insufficient ‘personal protective equipment’.
f. Lack of supervision.

Some unsafe working conditions are:
g.Bad housekeeping.
h.Inadequate guarding.
i. Lack of scaffolding.
j. Lack of training according to safe work
procedures.
k.Excessive noise, etc.

3.3 Software causes: Poor Communication
• Construction industry involves many parties therefore
effective communication is essential to overcome
these challenges.
• Poor communication can quickly isolate team
members, who become detached from the project
purpose, their roles, and the value of their
contributions.
• Poor communication in the workplace can result in
friction, frustration, confusion and a feeling of stress
and anxiety.

• Poor communication often causes employee
problems, project rework and jobsite accidents,
• Effects of poor communication in construction
may cause cost overruns, time overruns,
dispute and finally project failure.
• Communication failures have been blamed for
more than a thousand deaths in plane crashes.

• Communication is a key component to control
an emergency.
• Effective communication help to achieve
coordinated results, manage activity, motivate
workers and understand what needs to be done.
• Effective communication help better time and
cost management in achieving successful
project.

Communication with Employees
• Company’s safety policy should be made known to
each and every employee.
Company should communicate to employee that
• Worker’s safety is of importance to the company.
• Safety officers are assigned for looking worker’s safety.
• Company expects from employees to work safely and
cooperate to ensure safety.
• Communicate about safety program.

Some causes of poor communications
1.Objectives are not clear.
2.Poor leadership.
3.Cultural diversity in the workplace.
4.Demoralized employees.
5.Personal issues and challenges of
employees.

1.Objectives are not clear
• Employees also need to be made aware of
the objectives of the company.
• Clear objectives help employees to align
with company’s objectives and can
contribute to its progress and success.

2.Poor leadership
• Poor leader deteriorates communication in
the workplace.
• Poor leaders are indecisive and unable to
inspire and motivate their team.

Cultural diversity in the workplace.
• world is getting more and more diverse.
• Workers from different cultures, races,
religious beliefs in the same workspace may
be a cause of poor communications in the
workplace.

Demoralized employees
• Demoralized employee lose interest in the work.
• Demoralized employee feels unvalued,
disrespected and ignored despite their capacities
and talents.
• Demoralized employee tends to be irritate,
unproductive, and look for opportunity elsewhere.

Personal issues and challenges of employees
• Some employee may be distracted by their own
personal issues and challenges, such as a death
in the family or divorce.
• Due to distractions and personal issues, a staff
member may communicate the wrong way, and
react in a negative fashion.

3.3 Software causes: Lack of Training
• Most construction accidents are
preventable.
• Safety training and education is one of the
surest ways to prevent accidents.
• One of the common cause of accident at
construction sites is the lack proper training
to workers.

• Lack of training is often the cause of workers
falling from heights at construction sites.
• Falls from heights continue to be among the
leading causes of serious injuries and deaths
of construction workers.
• Untrained labor, carpenter, roofer, electrician,
painter, mason and others working at height
without safety gear may slip and fell to his death.

Training aspects for proper work
practice at work place include
1.Learning the use of equipment and
procedures that are new to the worker.
2.Learning the particular hazards that exist
on a job site.

Workers who aren’t properly trained:
i. may fail to recognize hazardous conditions.
ii. do not know how to safely handle the
recognized potential hazard.
• In either case, improper training can result
in catastrophic injury or death.

3.3 Software causes: Low level of education
of the worker
• Workers having low level of education include
labor, plumber, painter, bar-bender, tiler, welder,
mason, carpenter, mechanics, steel fixer and
plant operator etc.
• Relationship between education and accident
was studied by Marmara University, Turkey in
September 1999 in which most of the workers'
education was school level.

of the worker
• Result of the study revealed that level of
education of the worker is significantly
related with work accident.
• Education level of the workers who have
work accident is significantly lower than the
education level of workers who do not
have work accident.

of the worker
• The study identified that low level of
education of the worker is one of the cause
of the accident.

of the worker
Low level of education based causes of
accident
• Lack of motivation.
• Lack of training.
• Use of low quality tools and equipment.
• Negligence.
• Vulnerability to safety and health care services.

3.3 Software causes: Low skill of workers
Low skill of workers based causes of
accident
1.Unfair wages.
2.Lack of motivation and incentives.
3.Lack of training.
4.Use of low quality tools and equipment.

3.3 Software causes: Low skill of workers
Low skill of workers based causes of
accident
5. Unsafe act.
6. Overconfidence.
7. Errors and mistakes.
• Because of lack of adequate skill.
• Lack of interest on the job.
• Monotony (Boredom) etc.

3.4 Hardware causes: Unsafe Work Site,
Improper Tools and Equipment, and
Improper Storage of Materials
Hardware causes of construction
accident are due to:
i. Equipment
ii. Process
iii.Materials
iv.Physical condition of workers

3.4 Hardware causes of Accident
Hard ware causes of accident are related to
i. Men
ii. Machine
iii. Materials
Hardware causes may sub-divided as:
1. Physical causes
• Improper condition of machine.
• Improper use of machine.
• Improper use of tools for the job.
• Use of old and worn-out tools.
• Improper handling of materials like explosives, paints,
acids, bitumen etc.
50

2. Physiological causes (Related to human health)
Some physiological causes of accidents are due to:
• Poor eye sight of the worker.
• Poor health condition.
• Poor hearing condition.
• Old age.
• Under age children.
• Intoxication.
• Physical disability.
• Other sickness.
51

3. Psychological causes
• Workers should be mentally free, and do work with
absolute zeal and efficiency.
Some psychological causes of accidents are due to:
• Anxiety.
• Worries.
• Fear.
• Anxiety of competition.
• Peer relation.
• Relation with supervisor.
• Emotions.
52

Hardware causes of accident: Unsafe work site
• There are many causes of an accident on a unsafe
construction site.
• Many accidents at construction site happens due to
unsafe worksite, negligence, improper use of tools
or equipment, and lack of protective safeguards.
• Major causes of construction worker’s deaths at
work site were falls, struck by object, electric
shock, and caught-in/between two objects.
53

Causes of accident at unsafe work site
• Tripping hazards from construction
materials and debris.
• Missing guards or protections on power
tools.
• Unsafe equipment.
• Lack of protection for workers in trenches.
54

Causes of accident at unsafe work site
• Tripping hazards from construction
materials and debris.
• Missing guards or protections on power
tools.
• Unsafe equipment.
• Lack of protection for workers in trenches.
55

3.5 Accidents at Construction Site
• Construction accident may be defined as a
sad happening that was not properly
planned to be prevented.
• Most cases, most of the accidents in the
construction industry are preventable.
• Processes of prevention can and should be
planned.
56

• An unwanted event of any type that has taken
place can be called an accident.
• Loss of life or property or injury to health due to
unnoticed or neglected reason is an accident.
• An event that occurs by chance especially one
causing injury or damage’.
• In construction industry most these unhappy
happenings do not occur only by chance or
unknowingly.
57

• Improper clothing of work men.
• Negligence in using personal protective equipment.
• Congested workplace.
• Not maintained workplace causing slippery or
tripping.
• Poor light and ventilation.
• Obstructions in the working place.
• Projections and generally unsafe work place.
58

• Unsafe use of scaffolding and ladders.
• Improper scaffolds and ladders.
• Inadequate cofferdams.
• Inadequate shore during excavation.
• Undersized or not designed temporary works.
• Improper discipline among workers.
59

• Construction accidents are mostly known,
so construction accidents can be planned
for prevention.
• Some construction accident are unknown
i.e. not foreseeable hence such accidents
are not preventable.
60

1. Falling from Height
• Falling from working place.
• Falling from scaffolding.
• Falling from ladder.
• Falling from formwork.
• Falling from roof.
2. Hitting by falling object
• Falling materials.
• Falling tools.
• Falling materials from the edge of the trench.
61

3. Accidents with Machines
• Licensed operator.
• Proper operation.
• Condition of machine.
• Third party inspection.
• Safety devices: horn, side mirror, signal lights, etc.
• Guarded work place.
• Operating speed.
• Signaling.
• Signage.
• Proper clothing.
62

4. Accidents with Transport Vehicles
• Speed.
• Heavy load.
• Odd load.
5. Accidents with Blasting
• Qualified blaster.
• Designed charge.
• Controlled blasting.
• Safe hideout.
• Clearing of the area.
• Personal protective equipment (PPE).
63

6. Accidents with ‘under - water work’
• Drowning is common hazard.
• Provide mask.
• Provide adequate PPE.
• Certification by engineer is inevitable.
• Use of quality tools.
• Maintain electrical safety.
• Safety from animals.
64

7. Accidents with Chemicals
• Burn.
• Poison intoxication.
• Manufacturer’s certificate.
• Safe storage.
• Use by trained staff.
• Effect must be known.
• Antidote
• Care of gases and fumes.
• Always proper PPE.
• Knowledge and skill of supervisor.
65

8. Accidents with Deep Excavation
• Collapse of side walls.
• Falling of excavated materials from the edge.
• Falling of objects from the edge.
• Fall of persons from the edge.
• Confine area working.
• Light and ventilation.
• Number of persons are controlled - 2.25 sq. m/person.
• Safe access provided - inlet, outlet.
• Escape route provided - every 15 meters, 1 for 50 persons
• Dewatering.
66

9. Accidents with Fire hazard (the fire triangle)
Fire Safety: Maintain the followings:
• Petroleum, kerosene and other product should be stored
far from labour settlement and working area.
• Petroleum, oil, and lubricants (POL) should be stored
underground if in large quantities or in close metallic
containers if in small quantities.
• Only required quantities of such materials should be
purchased and stored.
• Timbers should be stored in an appropriate place but
sufficiently apart from POL products.
67

9. Accidents with Fire hazard
• Combustible substance like paints should be stored
and handled carefully.
• Combustible construction garbage should be
segregated.
• Bitumen boilers should be installed away from
settlement areas
• Heating of bitumen should be done in the presence
of a highly skilled and trained bitumen foreman.
68

• Smoking and other ignition sources should not be allowed
to go near the bitumen boiler and highly combustible
substance/liquid.
• Highly combustible gases should be handled properly by
the trained personnel only and the valves should be
checked whether they are closed when not in use.
• Fire safety charts should be displayed around the work
place and in the store area.
69

• Necessary fire protection equipment should be made
available to the workers.
• Fire fighting equipment should be installed at the
locations as planned by the safety office.
• Construction waste (combustible garbage).
• Electrical equipment – cut outs (circuit breakers).
• Fire safety plan.
• Fire safety training.
70

Fire Hazard Check Points
• Do the operations involve fire hazard?
• Does the project require storing of POL?
• Has the storage and working area been planned?
• Are proper solid waste receptacles provided?
• Is provision made for regular removal of waste material?
• Are the workers trained to save themselves against fire?
• Are there enough fire extinguishers in and around
workplace?
71

Fire Hazard Check Points
• Are the staff trained to use fire extinguishers?
• Has the fire escape been planned?
• Is secondary way-out safe if fire blocks normal route?
• Are the staff trained to take necessary precautions and
use safe access?
• Has periodical fire drill been done at work place?
• Has escape area well maintained? (House keeping)
72

Fire precautions during use of bitumen boilers
• Gas cylinders to be kept away from burner.
• Combustible materials to be kept away from burner.
• Boiler not to be transported whilst alight.
• Boiler not to be left unattended whilst alight.
• Adequate means of extinguishing to be provided.
• Boiler attendant to be trained to handle the fire
incidence.
73

Fire precautions during use of bitumen boilers
• Temperature indicators (thermometers) to be tested
periodically for their correctness
• Thinner not allowed to be added from the top on hot
bitumen while burners are alight
• Children and unauthorized persons not allowed to go
near the boiler
• Boilers to be kept away from settlement area
• Bitumen feeding system to be safe
74

Cranes and Lifting Equipment: Checkpoints
• Who is responsible for the inspections, are they carried out and
recorded?
• Has the test certificate been seen?
• Is the operator trained and competent?
• Are the controls (livers, handles, switches, etc.) clearly marked?
• Has the weight of the load been ascertained?
• Is the crane of more than 1 ton capacity?
• If so, and if it is a jib crane fitted with automatic safe load indicator in
an efficient working order, and is it being inspected every week?
75

• Is the crane sited on a hard level base?
• Has the signaller been trained to give signals and
to attach loads correctly?
• If the crane can vary its operating radius, are the
safe working loads and corresponding radii
plainly marked?
• Is the crane regularly maintained?
76

• Is the crane sited on a hard level base?
• Has the signaller been trained to give signals and
to attach loads correctly?
• If the crane can vary its operating radius, are the
safe working loads and corresponding radii
plainly marked?
• Is the crane regularly maintained?
77

Causes of fatal accidents at construction site
1. Fall
• Fatal accident happens due to lack of fall
protection for workers on the ground from
elevated structures.
• According OSHA, fall caused 40 of all deaths of
workers falling from a height and falls caused by
slips or trips e.g. scaffolds, ladders, roofs,
sidewalk bridges, or unprotected holes.
78

2. Electrical Hazard
• Fatal accident happens due to lack of safety
precautions at unsafe work site when working
near power lines.
• OSHA estimates 8.5 % of fatalities occur from
electric shocks including exposed wiring, wet
outlets, overhead power lines, and careless
maintenance relating to electrical currents.
79

3. Struck by objects
• Fatal accident happens due to struck by object
at unsafe work site.
• OSHA estimates 8.4% of fatalities occur from
falling, swinging, shifting, or misplaced objects,
along with equipment malfunctions or
vehicle/equipment strikes from forklifts, or other
heavy equipment.
80

4. Caught-in/between
• Fatal accident happens due to caught-in
between objects at unsafe work site.
• 1.4% of fatalities occur when construction
workers are crushed or caught-in/between
equipment, collapsing structures, or other
objects.
81

• Many of these tragedies can be prevented by
general contractors if they proactively plan and
put worker safety as a priority above skimping
on these measures to save money.
82

Direct Losses
• Payment made to replace, remake correct the
damage due to accident.
• Payment made as compensation for other’s
property.
• Payment made to the doctor and medicine cost
for the workers or by the workers.
• Losses of production by the injured worker after
the accident at the rate of cu. m per hour.

Direct Losses
• Loss of time and hence the production of the
fellow workers who stop work after accident to
attend the effected fellow worker or to correct
the situation.
• Losses due to damage caused to the
machinery.
• Losses to the worker of his wages for the period
he cannot work.

Indirect Losses
• Loss of time of fellow workers who stop or slow
down the work because of curiosity or to show
sympathy.
• Loss of supervisor’s time who has to attend the
injured worker.
• Loss of supervisor’s time and other expert’s
time for investigation of the accident and
preparing a report.

Indirect Losses
• Loss of time in making alternative arrangement
because of the accident.
• If accident causes death or permanent disablement
of the worker, losses will occur to recruit and train a
new worker.
• Losses due to the reduction in the efficiency of fellow
workers due to low morale.
• Pain felt by the injured worker which can never be
compensated.

Social Losses
• Family may go economically dependent.
• Children may loose education.
• Women may be forced to go for illegal/immoral
act/work.
• Old parents may die of shock.
• Mental attitude may change even after recovery
from accident.

Social Losses
• Others may be affected by the horrified
accident.
• Festivals or Jatras may get affected.
• Family may go economically dependent.
• Children may loose education.
• Old parents may die of shock.

Social Losses
• Women may be forced to go for illegal/immoral
act/work.
• Mental attitude may change even after recovery
from accident.
• Others may be affected by the horrified
accident.
• Festivals or Jatras may get affected.

3. Accidents and Their Causes
End of Chapter 3

Causes, Prevention of Workplace Accidents

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