Falls from Height - Workplace Safety and Health Council

PREFACE
This compilation of case studies on fatalities in the construction industry
is initiated by the Workplace Safety and Health Council, and put together
by the WSH Construction Committee in collaboration with the Ministry
of Manpower. This booklet depicts how the accidents occurred and
provides valuable learning points on how they may have been prevented.
This is the first in a series of such booklets to be published.
As much as the next few years promise to be exciting for the construction
industry, they also pose a great challenge to the industry to maintain
workplace safety and health. Construction sites have customarily been
viewed as high-risk workplaces, which more often than not have a higher
incidence of workplace fatalities. We must address this perception and
change the reality. While construction workers strive to complete a building
or facility, it is important that they do not risk life and limb. It is crucial
that these workers go home safely after work each day.
This booklet of case studies offers insights to all in the industry on how
these tragic accidents occurred, so that we may glean important, lifesaving
lessons from the experience. In learning from our past mistakes,
we can and must prevent these mishaps from happening again. Together
with your help, we can transform construction sites into safe and healthy
workplaces for our workers.
Mr Lee Tzu Yang
Chairman
Workplace Safety and Health Council

CONTENTS
Falls from Height
Case 1 Fall through a roof 04
Case 2 Fall from a scaffold 06
Case 3 Tripped by an electrical extension 08
Case 4 Fall of formwork 10
Case 5 Fall off a toppling scaffold 12
Case 6 Killed by a plunging hoist 14
Case 7 Fall through an opening 16
Case 8 Fall from a scaffold 18
Case 9 Collapse of a platform 20
Case 10 Fall from a formwork shoring 23
Case 11 Tipping and fall of a table formwork 26
Case 12 Fall of a formwork panel 29
Case 13 Fall through an open side 32
Case 14 Fall from a scaffold 35
Case 15 Hit by a rubber hose 38
Case 16 Fall from an open side 41
Case 17 Fall off an open platform 44
Case 18 Fall through a skylight 47
Case 19 Fall from an attic 49
Case 20 Fall due to an unstable scaffold 51
Case 21 Fall while dismantling a platform 54
Case 22 Fall of a gondola platform 57
Case 23 Fall from a scaffold 60

FALLS FROM HEIGHT

CASE 1
FALL THROUGH A ROOF
Description of Accident
A worker was installing lifelines
on a pitched roof at a worksite.
He stepped on one of the roof
tiles which then broke under his
weight. The worker suffered
severe head and chest injuries
and eventually succumbed to
the injuries.
Causes and Contributing
Factors
1. Roof tiles removed
• When the worker went up the
roof to install the lifelines,
he had stepped onto the
midsection of the roof tiles
where there was no support
structure. The roof tile hence
broke under his weight.
1
• He fell from a height of
4.8m through the roof.
2
1. Height of fall = 4.8m
2. Place where the deceased worker landed
04

Root Cause Analysis
Evaluation of loss
Type of contact
Immediate cause(s)
Basic cause(s)
Failure of SMS
• One worker killed
• Fall from height to lower level
• Improper position for task
• Lack of experience
• Inadequate work standards
• Inadequate leadership and/or supervision
• Hazard analysis and risk assessment
Follow-up
A Stop Work Order was issued to stop all work at the premises.
The main contractor was instructed to conduct risk assessment and
develop safe work procedures for removing roof tiles which
contained asbestos.
Recommendations
Conduct a proper risk assessment prior to the commencement
of a job.
Use a boom lift to send workers to the roof-top to install the lifelines
instead of working directly on a pitched roof.
Use crawl boards or ladders provided on rooftops for safe access
by the workers.
05

CASE 2
FALL FROM A SCAFFOLD
Description of Accident
A worker was intending to paint
the walls adjacent to a ledge. He
tried to climb out of a suspended
scaffold onto the building ledge
but lost his footing and fell from
the nineth storey of the building.
Causes and Contributing
Factors
• The worker was not wearing
any safety harness or safety belt.
• The suspended scaffold had
last been examined in August
2002, contrary to the legal
requirement which states
that such equipment must be
thoroughly examined and
certified for use by an approved
person once every 12 months.
1. The deceased landed here
2. The suspended scaffold was
re-positioned here
3. The position of the suspended scaffold
at the time of the accident
1. The lifeline installed outside the
suspended scaffold
2. A lifeline installed in between the ledges
and kitchen area
3. A worker attached the fall arrestor
device to a lifeline
4. One of the cross beams
5. The suspended scaffold installed at
the façade
1
2
3
1
2
3
4
5
06

Root Cause Analysis
Evaluation of loss
Type of contact
Immediate cause(s)
Basic cause(s)
Failure of SMS
• One worker killed
• Fall from height to lower level
• Improper position of worker for task
• Inadequate or improper protective equipment
• Lack of knowledge
• Inadequate leadership and/or supervision
• Hazard analysis and risk assessment
• WSH rules, permits and
personal protective equipment
Follow-up
A Stop Work Order was issued which required the occupier to
conduct hazard analyses and develop safe work procedures for
the above works.
The occupier was required to engage an approved person to
examine the suspended scaffolds in the worksite.
Recommendations
Provide safe access and egress routes for workers.
Install an independent lifeline for anchoring personal fall
protection equipment.
Brief workers on the hazards and risks of the job.
07

CASE 3
TRIPPED BY AN ELECTRICAL EXTENSION
Description of Accident
A worker was carrying out drilling
operations at the 33rd level of a
building. While he was searching
for an electrical socket outlet to
connect an electrical tool,
he accidentally tripped on
an electrical extension wire that
he was holding and fell through
an opening within a wooden
barricade. He landed below
on the 32nd level.
Causes and Contributing
Factors
• The 33rd level floor slab opening
measured approximately 4m in
length and 2.7m in width. The
depth from the 33rd level to
the 32nd level measured
approximately 4m.
• The floor slab opening was meant
for the staircase before it was
dismantled. It was not guarded
by any effective barrier to
prevent falls.
1. The electrical distribution box
at the corner of the floor slab opening
2. Partition wall beside the floor slab
opening
3. The floor slab opening was meant for
a staircase before it was dismantled
4. The 32nd level worksite below
1. The electrical distribution box at the
corner of the floor slab opening
2. The red-white tape and nylon rope
used to barricade the two sides of
the floor slab opening
3. The "Danger No Entry" signage
4. The wooden barricade (guarding
only one side of the opening and
not the remaining three)
1
2
3
4
1
2
3
4
08

Root Cause Analysis
Evaluation of loss
Type of contact
Immediate cause(s)
Basic cause(s)
Failure of SMS
• One worker killed
• Fall from height to lower level
• Inadequate guards or barriers provided
• Improper placement
• Lack of knowledge
• Communication/group meeting
• WSH training and competence
Recommendations
Provide barriers to guard floor openings to prevent falls or cover
floor openings with a cover (if appropriate).
Provide appropriate lighting and display suitable warning signs to
warn operators of potential dangers at the work area.
09

CASE 4
FALL OF FORMWORK
Description of Accident
A site supervisor and a worker were
killed when a jumpform panel that
they were working on fell off from
its position to the ground below.
The jumpform was fixed at the
16th storey of a building that was
under construction at the time
of the accident.
Causes and Contributing
Factors
• The jumpform panel that dropped
was one of the two panels that had
been shifted from the 15th storey
of the building using a tower
crane in the morning prior to
the accident.
1. Injured was caught in the net here
below the third storey
• Investigations revealed that the
bracket of the collapsed jumpform
panel was not securely attached
onto its support mechanism. As
a result, the bracket slipped off
from its support and the entire
panel fell off subsequently.
• Significant changes were noted
during the installation process
of the formwork which
affected its integrity.
1. Jumpform fell off from here
10

• The subcontractor did not
conduct hazard analysis or
develop safe work procedures
for the new installation process.
Root Cause Analysis
Evaluation of loss
Type of contact
Immediate cause(s)
Basic cause(s)
Failure of SMS
• One worker killed
• Fall from height to lower level
• Failure to secure jumpform
• Lack of skill
• Inadequate leadership and/or supervision
• Inadequate monitoring of construction
• Hazard analysis and risk assessment
• WSH practices and procedures
• WSH training and competence
Follow-up
The occupier was instructed to review the design of the formwork
system and to revise the safe work procedures for the workers before
work on the jumpform structure was allowed to continue.
Safety measures such as additional brackets and wire ropes for
securing purposes were also introduced to increase system reliability.
Recommendations
Develop safe work procedures.
Conduct proper supervision of the erection process and checking
of the panel support.
Ensure that the bracket hook’s design is such that it can be
checked easily.
11

CASE 5
FALL OFF A TOPPLING SCAFFOLD
Description of Accident
A worker was assigned to service
some roof painting work at a
building. He was erecting a mobile
scaffold along a corridor at the
fourth storey of the building when
the scaffold toppled. As a result,
the worker fell off from the scaffold
and out of the building onto the
ground 12m below.
Causes and Contributing
Factors
• The mobile scaffold (with a
cantilevered structure) was not
in a stable position and was not
secured to the building structure
or metal railing along the
building corridor at the time
of accident.
1. The fourth storey roof beam
2. The toppled mobile scaffold at
the fourth storey corridor
3. The factory building
4. The location where the deceased
had landed
5. The driveway
12
• When the worker climbed onto
the mobile scaffold to tie the
metal deckings to the cantilevered
structure, the mobile scaffold
toppled and the worker fell off
from the scaffold and building.
1. The toppled mobile scaffold with the
cantilevered structure
2. The two metal decking which were
to be tied
3. The fourth storey corridor
4. The parapet wall
5. The castor wheels

Root Cause Analysis
Evaluation of loss
Type of contact
Immediate cause(s)
Basic cause(s)
Failure of SMS
• One worker killed
• Fall from height to lower level
• Improper position for task
• Inadequate or improper protective equipment
• Failure to secure scaffold
• Lack of experience
• Inadequate work standards
• Communication/group meeting
• Hazard analysis and risk assessment
• WSH training and competence
Follow-up
The main contractor was instructed to conduct a risk assessment
and review the safe work procedures for all works at the site.
Recommendations
Conduct risk assessment prior to job commencement.
Use an alternative method of work, or institute safe work
procedures for such work.
Ensure proper safety measures are in place such as securing of
mobile scaffold to the building structure and provision of lifelines
for the workers.
13

CASE 6
KILLED BY A PLUNGING HOIST
Description of Accident
A worker, employed as a plasterer,
was seen moving up in the
Passenger and Material (PM) hoist.
The PM hoist suddenly plunged to
the ground and the worker died
on the spot.
Causes and Contributing
Factors
1. The control unit
• The PM hoist involved in the
accident had been retrofitted by
the hoist supplier with a machinery
plate with a motor drive unit and
a safety device.
• The most probable cause of the
accident is the failure of the
mounting bolts of the machinery
plate. The fracture of these
bolts caused the machinery plate
to detach from the hoist cage.
• The hoist cage slammed onto
the top of the drive unit, and
knocked off the machinery plate
with the drive unit from the rack,
resulting in the free-falling
of the hoist.
1. The dislodged machinery plate
14

Root Cause Analysis
Evaluation of loss
Type of contact
Immediate cause(s)
Basic cause(s)
Failure of SMS
• One worker killed
• Fall from height to lower level
• Defective tools, equipment or materials
• Inadequate maintenance
• Excessive wear and tear
• Maintenance regime of machinery
Follow-up
A Stop Work Order was issued to cease all hoisting operations
installed onsite.
The occupier was instructed to dismantle all hoists and replace
them with another brand from another supplier.
Recommendations
Have a regular maintenance system as per maintenance regime
of CP79.
Replace bolts when installing the PM hoist at a new location.
15

CASE 7
FALL THROUGH AN OPENING
Description of Accident
A worker was to carry out painting
work. While he was getting ready
to paint the wall at the void area,
he fell into the opening at the
10th level and landed about 30m
below on a platform.
Causes and Contributing
Factors
• Directly above the platform were
openings which were found at
all levels from the first level to the
12th level. The opening measured
about 700mm x 900mm.
• The painting supervisor did
not check the work area to
be plastered/painted for
compliance to the safety
requirements listed in the
Permit-to-Work.
• The worker was not wearing a
safety belt/harness. He had been
working on site for two weeks
prior to the accident. Investigations
revealed that the worker had not
attended the Safety Orientation
Course (construction).
1. External scaffolding
2. Desceased was found lying at the
platform of the external scaffolding
3. Passenger hoist
1. External scaffolding
2. Guardrail
3. External wall
4. Void area
5. Barricade of wire rope with orange
netting
16

Root Cause Analysis
Evaluation of loss
• One worker killed
Type of contact
• Fall from height to lower level
Immediate cause(s) • Improper position for the task
• Inadequate or improper protective equipment
Basic cause(s) • Lack of knowledge
• Inadequate leadership and/or supervision
Failure of SMS
• WSH practices and procedures
• Hazard analysis and risk assessment
• WSH training and competence
Follow-up
The occupier was instructed to review the Permit-to-Work system
on site and implement it on a daily basis.
The occupier was instructed to only engage painters who have
attended the safety orientation course at the worksite.
Recommendations
Ensure all workers attend the Construction Safety Orientation Course.
Implement a safety induction programme on the use of personal
protective equipment prior to starting work.
Supervisors should be responsible to check and ensure the use
of appropriate personal protective equipment.
Conduct regular briefings on the dangers of working at heights.
17

CASE 8
FALL FROM A SCAFFOLD
Description of Accident
Worker A and his co-workers
were instructed to tidy up metal
scaffolds above a courtyard area
at a worksite. The group took up
their positions on the metal
scaffolds and the worker was then
on a scaffold next to the classroom
block. Worker A was to work on
the working platforms at the
fifth lift of the scaffold next to
the classroom block. He fell to
his death and was found lying on
the ground at the first storey.
1. The loose frame scaffold that was to be
removed by the deceased
2. A patched wall tie hole where the
cement was still wet
3. The working platform at the fifth lift of
the scaffold where the deceased had
stood on when working on the scaffold
18
Causes and Contributing
Factors
• The location that Worker A
landed was right below the
scaffold that he was working on
and the ground was scattered
with damaged cross bracings,
metal decking, scaffold frames
and metal pipes.
• The group of workers wore
safety belts but there was no
lifeline found on the scaffolds for
them to anchor their safety belts.
1. The deceased was working on the working
platform laid on the fifth lift of the scaffold
2. The corridor where the dismantled
scaffolding items were stored
3. A wall tie at the second lift of the scaffold
4. The deceased had landed here where
the scaffolding items had scattered

• The workers were not trained
scaffold erectors and had not
undergone any course for
scaffold erection.
Root Cause Analysis
Evaluation of loss
Type of contact
• One worker killed
• Fall from height to lower level
Immediate cause(s) • Improper use of personal protective equipment
Basic cause(s)
Failure of SMS
• Lack of knowledge
• Lack of skill
• WSH training and competence
• Hazard analysis and risk assessment
Follow-up
The occupier was issued with a Stop Work Order to install lifelines
on the scaffold and to engage trained scaffold erectors to dismantle
the scaffolds.
Recommendations
Install independent lifelines.
Supervisors should be responsible to check and ensure the use of
appropriate personal protective equipment.
Conduct regular briefings on the dangers of working at heights.
19

CASE 9
COLLAPSE OF A PLATFORM
Description of Accident
Three workers were carrying out
installation of a clothes drying rack
at the 10th level of an HDB flat. The
installation was done from a mast
climbing platform in the worksite.
Upon completion of the work, they
were about to descend when the
platform suddenly came down.
All three workers fell; two of them
died while the other was injured.
1. The platform had split open after
the incident
Causes and Contributing
Factors
• The bottom motor of the drive
unit of the platform was not
the original motor fitted to
the platform.
• The gearboxes of both the top
and bottom motors were
produced by the same
manufacturer, but were of
different type.
• The top motor was a two stage
gearbox while the bottom motor
was a three stage gearbox. Use of
these two gearboxes with different
output speed induces great stress
within the gears in the gearboxes.
1. Top motor
2. Bottom motor
20

• The moment the gearboxes
failed, the platform
descended suddenly and
crashed to the ground.
Root Cause Analysis
Evaluation of loss
Type of contact
• Two workers killed and one injured
• Fall from height to lower level
Immediate cause(s) • Defective tools, equipment or materials
Basic cause(s)
Failure of SMS
• Inadequate maintenance
• Inadequate replacement of unsuitable
materials
• Maintenance regime
• WSH practices and procedures
Follow-up
A Stop Work Order was issued.
The occupier was instructed to stop using all mast climbing work
platforms (MCWP) at the worksite.
The occupier was also instructed to carry out the following:
• To inspect all MCWPs and make good any defect found.
• To inspect that all motors in each drive unit of every MCWP used
at the worksite were of the same type.
• To have the MCWP inspected, examined and certified by an
approved person prior to the start of work.
21

Recommendations
Conduct functional checks, regularly, and before use.
Ensure that the specifications of the different units of any
equipment are compatible.
Have fall protection equipment as an additional safety measure.
22

CASE 10
FALL FROM A FORMWORK SHORING
Description of Accident
Worker A and his co-worker were
involved in the transfer of three
units of formwork shoring from the
third storey to the second storey
of the building that was under
construction.
They were climbing up the frame
of a unit of the formwork shoring
on the third storey so as to attach
the hooks of the chain slings
from the tower crane when the
formwork shoring suddenly
tilted and toppled to the floor.
Worker A fell from the shoring
and landed on the third storey.
He sustained serious head
injuries from the fall and died
on the spot. The other worker
suffered minor scratches as he
managed to jump to the floor
as the shoring toppled.
Causes and Contributing
Factors
1. The deceased landed here
2. The toppled formwork shoring
1. The toppled formwork shoring
2. Width: 1.2m
3. The inner props
• Worker A was standing on
a formwork frame about 4.28m
from the floor when the
shoring toppled.
23

• The ratio of the height of the
shoring against its width was
about 4.74m. It was tall
and slim and hence prone
to toppling.
• There was no outrigger
installed on the shoring to
ensure the stability of the
shoring. It was thus unsafe
for workers to work on
the shoring.
• The worker who was to rig up
the shoring had not attended
the Rigging Operation Course
and he was not an appointed
rigger. There was no lifting
supervisor appointed for the
transfer of shoring using the
tower crane.
Root Cause Analysis
Evaluation of loss
Type of contact
Immediate cause(s)
Basic cause(s)
Failure of SMS
• One worker killed and one injured
• Fall from height to lower level
• Failure to secure shoring
• Lack of knowledge
• Inadequate work standards
• Inadequate leadership and/or supervision
• Hazard analysis and risk assessment
• WSH training and competence
24

Follow-up
To prevent recurrence, the factory occupier was instructed to
implement the following safety measures:
• Provide ladders on the shoring or riggers to gain access to a
higher level for rigging up the shoring.
• Provide working platform of at least 635mm width as foothold
on the shoring for the riggers.
• Appoint a qualified lifting supervisor to co-ordinate the
lifting of the shoring before the commencement of work.
• Appoint qualified riggers to carry out the rigging work.
Recommendations
A safe width to height ratio must be ensured.
Proper access such as a monkey ladder should be provided.
25

CASE 11
TIPPING AND FALL OF A TABLE FORMWORK
Description of Accident
Worker A and his co-worker were
working on a table form
(formwork) that was partially set
up on the eighth level. The table
form tipped towards the edge of
the building and fell to the ground.
Worker A fell together with the
table form and landed on the
ground. He died on the spot.
Causes and Contributing
Factors
1. The metal frames of the table form that
fell from the eighth level
• The table form was not set
up on the eighth level in
accordance with the design of
the professional engineer.
• The formwork subcontractor
claimed that due to space
constraints, the position of the
front props for the table form
could not be put up according
to the design of the professional
engineer. However, the
subcontractor did not request
the professional engineer to
redesign the table form to suit
the actual site situation.
1. The rear corner props
2. The intermediate props
3. The front corner props
26

• According to the design, while
setting up the table form,
four props at the four corners
were to be put up first followed
by two intermediate props.
However at the time of
accident, the table form
was supported by two
props at the rear corners
and two placed at intermediate
positions.
• The position of Worker A
and his co-worker were outside
the four supporting points
and the combined weight
caused the table form to tip
over and fall over the edge
of the building.
Root Cause Analysis
Evaluation of loss
Type of contact
Immediate cause(s)
Basic cause(s)
Failure of SMS
• One worker killed
• Fall from height to lower level
• Improper placement of table form
• Inadequate evaluation of changes
• Hazard analysis and risk assessment
27

Follow-up
A Stop Work Order was issued to stop work on the table form.
The occupier and subcontractor were instructed to implement
the following safety measures:
• To redesign the table form using a professional engineer.
The revised design should enable it to be supported by
four props at the four corners.
• To ensure that a formwork supervisor is present to supervise
the erection of the formwork at the site.
• To conduct safety training to instruct the supervisors and
workers on the proper way to set up the table forms.
Recommendations
Ensure that a table form is fully supported by all necessary
props at all times.
Ensure formwork supervisor is present at all times to supervise
the proper erection of the formwork at the site.
Conduct safety training to instruct supervisors and workers on the
proper way to set up the table forms.
28

CASE 12
FALL OF A FORMWORK PANEL
Description of Accident
A worker was involved in the
dismantling of metal formwork
panels. He was standing on the
working platform of a metal
formwork panel when the panel
gave way. He fell about 6m
together with the panel and
it landed on him. He died on
the spot.
Causes and Contributing
Factors
1. Working platform at the top section
2. Modular formwork panels
• Investigations revealed that
the day prior to the accident,
the tie rods at the top section
of the formwork structure had
been removed. The stability of
the formwork structure was
compromised as a result.
• The foreman had noticed this
but he did not proceed to
check the tie rods at the top
section of the other panels of
the formwork structure,
although he was aware that
something was amiss.
1. Connecting brackets between internal
and external formwork panels
2. Deceased was standing around this
position on the working platform of the
formwork panel prior to the incident
3. The formwork panel had “peeled” off,
exposing the concrete wall
4. The deceased fell about 6m to the
first level. The formwork panel also
came down and landed on him
29

• As the worker was standing
on one end of the working
platform of the formwork
panel, the formwork panel
peeled off from the concrete
wall structure. The worker
lost his balance and fell from
the working platform. The
formwork panel also came
down and landed on him.
Root Cause Analysis
Evaluation of loss
Type of contact
Immediate cause(s)
Basic cause(s)
Failure of SMS
• One worker killed
• Fall from height to lower level
• Failure to secure formwork
• Inadequate work standards
• WSH practices and procedures
30

Follow-up
The occupier was instructed to implement the following
improvements/measures at the worksite:
• A written work procedure on the installation and dismantling of
the formwork system to be instituted and implemented at their
worksites.
• Warning signages to be installed at the top section of the
formwork structure to remind workers not to remove the tie rods
at the top section prior to hoisting by a tower crane.
Recommendations
Ensure that the formwork supervisor closely supervises the work.
Check and secure all formwork at all times.
Use written work procedures and signage to remind workers not
to remove tie rods.
31

CASE 13
FALL THROUGH AN OPEN SIDE
Description of Accident
Worker A and his co-worker
were getting ready to carry out
plastering work to a column
on the fifth level of a building
at a worksite.
Subsequently Worker A was
seen falling through the open
side next to the column to be
plastered. He landed on the
ground level 15m below and
died subsequently.
1. Fifth level
2. Open side
3. The deceased was found here
Causes and Contributing
Factors
• The open side where the worker
fell off was not barricaded.
• There was a lot of building
materials, wooden pallets,
formwork materials and other
materials placed on the floor
on the fifth level. These materials
were placed haphazardly and
obstructed access. Worker A
had to maneuver his way
through these materials to
his workplace.
1. Column to be plastered
2. Open sides
3. Scaffold
32

• Worker A was last seen
standing at the column near
the open side, holding his
safety belt in his hand. He was
seen falling off the edge.
• The accident probably
occurred when Worker A was
inspecting the column located
next to the open side. He may
have tripped on some object
on the ground and lost his
balance.
• A similar accident had
happened three months ago.
Root Cause Analysis
Evaluation of loss
Type of contact
• One worker killed
• Fall from height to lower level
Immediate cause(s) • Inadequate guards or barriers
Basic cause(s)
Failure of SMS
• Inadequate work standards
• Inadequate storage of materials
• Poor housekeeping
• WSH practices and procedures
Follow-up
The occupier was instructed to carry out the following:
• To cover all openings and put up barricades for open
sides on site.
• To place materials properly so as not to obstruct the passageway.
• To carry out housekeeping regularly on site.
33

Recommendations
Provide barricades with rigid materials for all open sides and
secure at both ends.
Stack materials properly.
Clear debris frequently.
Ensure close supervision so that personal protective equipment
are used correctly.
34

CASE 14
FALL FROM A SCAFFOLD
Description of Accident
Worker A and his two co-workers
were involved in the dismantling
of an external scaffolding of a
block. One of the co-workers
descended from the scaffold and
called out to Worker A and another
co-worker to come down from
the scaffold for lunch.
As the co-worker was waiting at
the foot of the block, Worker A
fell from the scaffold and hit him.
Worker A was seen bleeding from
the back of his head and was
sent to the hospital where he
subsequently passed away.
1. Block 10
2. External scaffolding being dismantled
Causes and Contributing
Factors
• The scaffold supervisor was
not with the worker when the
dismantling work was in
progress. He had left the
worksite to buy lunch for his
workers.
1. External scaffolding
2. The deceased was found here
• Worker A was found with
his safety harness on his waist
after the accident.
35

• There were no eye-witness
accounts as to how Worker A
fell from the scaffold. Upon
hearing his co-worker’s call to
come down, the worker might
have detached his safety
harness from the lifeline.
The accident probably
happened when he was
descending from the scaffold,
and lost his footing. When he
fell, he hit the scaffold along
the path of his fall and hit the
worker who was waiting at the
foot of the block.
• Worker A and one of the
co-workers involved in the
dismantling work had not
undergone any training course
for the work. The safety
manager and the scaffold
supervisor were aware that
the two workers did not have
scaffold erectors certificates.
It was reported that the
workers were scaffold
assistants and were expected
to be stationed on the
ground, not on the scaffold.
Root Cause Analysis
Evaluation of loss
Type of contact
• One worker killed
• Fall from height to lower level
Immediate cause(s) • Making safety devices inoperative
Basic cause(s)
Failure of SMS
• Lack of knowledge
• Lack of skill
• Inadequate supervision
• WSH training and competence
36

Follow-up
The occupier was instructed to engage only trained scaffolders to
carry out the scaffolding work on site.
Recommendations
Assign only certified erectors to carry out dismantling work.
Provide proper training.
37

CASE 15
HIT BY A RUBBER HOSE
Description of Accident
A concrete pump operator and
his co-workers were carrying out
cleaning work on a platform which
was erected about 10m above
the bottom of the shaft.
The cleaning work was carried out
by means of inserting a sponge
ball into one end of the pipeline
and feeding the pipeline with
compressed air. The other end
of the pipeline was equipped
with a rubber hose to discharge
the leftover concrete into a
container. The workers were
gripping the rubber hose while
the pump operator held down
the rubber hose with a steel tube.
When the sponge ball was
forced out from the rubber hose,
the hose swung suddenly and
hit the pump operator. He was
flung off the platform and
landed on the bottom of the
shaft. He died on the spot.
1. Concrete pump
2. Rubber hose
3. Timbers on the platform
4. Scaffold frame
1. Deceased was standing here prior
to the accident
2. Rubber hose was placed on a
scaffold frame
38

Causes and Contributing
Factors
• There were some pieces of
timber placed on the platform
where the cleaning work
was carried out. Workers
mentioned that it had, to some
extent, hampered their work.
• Investigations revealed that
the rubber hose was not
secured in position to prevent
it from moving during the
cleaning operation.
• Towards the end of the
cleaning operation, particularly
at the time when the sponge
ball was forced out from the
hose, the sudden release of the
compressed air probably
created some lateral forces. This
caused the hose to swing and
resulted in the workers losing
their grip on the hose.
• The hose swung and hit the
pump operator, pushing him
over the guardrail.
Root Cause Analysis
Evaluation of loss
• One worker killed
Type of contact
• Fall from height to lower level
Immediate cause(s) • Failure to secure the rubber hose
• Poor housekeeping
Basic cause(s) • Improper storage of materials
• Inadequate work standards
Failure of SMS
• WSH practices and procedures
• Hazard analysis and risk assessment
39

Follow-up
The occupier was instructed to submit safe work procedures (SWP)
for pipeline cleaning work involving compressed air and to
implement and ensure that all the workers adhered to
the SWP.
Recommendations
Ensure at least two tag lines to hold the end of the rubber hose
in position.
Workers should be provided with and trained in the use of fall
protection equipment.
Ensure close and continuous supervision of such hazardous
operations.
40

CASE 16
FALL FROM AN OPEN SIDE
Description of Accident
A subcontractor was engaged
to carry out block-laying and
plastering works at Blocks A and
B of a building site. The foreman
had given instructions to a worker
at Block A to clear some wooden
palette at the workplace after
which he walked towards Block B.
About five minutes later, the
foreman was seen sitting on top
of a pile of debris at the second
storey of Blk B. He was bleeding
on the left side of his head and
was pronounced dead by the
ambulance officer.
1. Open side
2. Debris
3. Precast concrete components
Causes and Contributing
Factors
• A wooden pallet was found
broken among the pile of debris
at Block B. There were fresh blood
stains on the pallet. A worker
confirmed that he found the
foreman on the broken palette.
• The pile of debris was situated
right below a side of the building
with a series of open sides.
1. The deceased was found here
41

• Investigations revealed that
the open sides at the seventh
storey were barricaded. All
the other open sides at
Block B, i.e. first to sixth storey
and the eighth storey were
not barricaded.
• Debris was also seen placed
close to the edge of an
open side on the seventh
storey of Block B. The debris
could fall and potentially
hit a person standing below.
• The foreman was believed
to have fallen from one of
the open sides. He might have
lost his footing when he was
working near an unbarricaded
open side at Block B. He may
have fallen and landed on the
pile of debris at the second
storey of Block B.
Root Cause Analysis
Evaluation of loss
• One worker killed
Type of contact
• Fall from height to lower level
Immediate cause(s) • Inadequate guards or barriers at open sides
• Poor housekeeping
Basic cause(s)
Failure of SMS
• Inadequate work standards
• WSH practices and procedures
42

Follow-up
The occupier was instructed to undertake the following
improvements to the work practices/conditions at the site:
• Cover openings/put up barricades to open sides on site.
• Remove loose materials from the edge of the buildings.
• Carry out proper housekeeping on site.
Recommendations
Provide barricades with rigid materials to all open sides and secure
at both ends.
Develop proper method statements on putting up barricades.
Stack materials properly.
Debris to be cleared frequently.
There should be close supervision to ensure that personal protective
equipment are used properly.
43

CASE 17
FALL OFF AN OPEN PLATFORM
Description of Accident
A worker was engaged to carry
out painting work in a school
building. He was assigned to paint
the roof purlins and the supporting
metal frames for a featured roof
located above the staircase roof
slab of a six-storey building. He
was later found lying at the foot
of the building with serious injuries
and was pronounced dead by
ambulance officers.
1. Purlin near the edge of the featured roof
Causes and Contributing
Factors
• Investigations revealed that a
scaffold with a working platform
had been erected below the part
of the featured roof that was
protruding beyond the staircase
roof slab.
• There was no guardrail erected
on the open side of the working
platform to prevent falls. There
was also no ladder provided on
the scaffold for access to the
working platform.
1. The featured roof
2. Purlin near the edge of the featured roof
3. Working platform on the scaffold
4. The staircase roof slab
5. Roof slab above the sixth storey
3
44

• It is probable that prior to the
accident, the worker had gone
up to the working platform
on the scaffold to paint the
purlin that was located near
the edge of the featured roof.
While painting the purlin,
he may have fallen over the
open side of the working
platform and landed at the
foot of the building.
Root Cause Analysis
Evaluation of loss
Type of contact
Immediate cause(s)
Basic cause(s)
Failure of SMS
• One worker killed
• Fall from height to lower level
• Inadequate guard or barrier
• Inadequate engineering
(inadequate assessment of loss exposures)
• WSH practices and procedures
45

Follow-up
Occupier was instructed to implement the following safety
measures:
• The scaffold should be properly erected and used for painting
the purlin and metal frames located near the edge of the roof.
• Guardrails of at least 1.1m height should be erected on the open
sides of the working platform and the staircase roof slab, to
prevent fall of persons working there.
• Access ladders should be provided for the workers to reach the
working platform.
• Painters should anchor their safety belts while working on the
working platform.
Recommendations
Provide lifeline for all work at heights.
Brief workers regularly on the use of personal protective equipment
and fall protection measures.
Erect scaffolds with proper access and guardrails.
46

CASE 18
FALL THROUGH A SKYLIGHT
Description of Accident
Worker A and three other
co-workers, each carried a pail
containing waterproofing material
up a roof in preparation for the
coating of the skylight of a roof.
While they were on the roof,
one of the co-workers heard a
breaking sound coming from
the roof sheets. He turned his
head and saw a broken skylight.
Worker A had fallen through the
skylight of the roof (at a height
of 8m) and landed on the ground.
Causes and Contributing
Factors
1. This row of skylight was to be
waterproofed
2. Location where the deceased fell
through the skylight
• Investigations revealed that prior
to starting work, the site supervisor
had briefed the workers not to
step on the skylight.
• Investigations revealed that
no safety measures such as
crawling boards or planks had
been provided as foothold for
the workers to stand on while
working on the roof.
1. The deceased fell about 8m and
landed here
47

• According to the workers,
the site supervisor told them
that there were no anchorage
points on the roof and hence
they would not be able to
use their safety belts while
working on the roof.
Root Cause Analysis
Evaluation of loss
Type of contact
Immediate cause(s)
Basic cause(s)
Failure of SMS
• One worker killed
• Fall from height to lower level
• Inadequate or improper protective equipment
• Inadequate work standards
• WSH practices and procedures
• WSH training and competence
Follow-up
The occupier was instructed to implement a written safe work
procedure immediately.
The employer was instructed to provide suitable crawling boards
or planks and to install suitable and sufficient anchorage points/
lifelines on the roof.
Recommendations
Install appropriate lifelines and anchorages.
Provide crawling boards, planks or ladders as a foothold for
workers working on the roof.
48

CASE 19
FALL FROM AN ATTIC
Description of Accident
Worker A, seven other co-workers
and a signalman were doing
concreting work on the roof beams
of a building at a worksite.
While waiting for a truckload of
concrete, Worker A was seen resting
on the staircase at the attic. Moments
later, Worker A was found on the
ground bleeding from his head.
Causes and Contributing
Factors
• The workers confirmed that
they were not wearing safety
belts while carrying out the
concreting work. Even if they
had worn their safety belts,
there was no anchorage point
for them to secure their
safety belts.
• There were no working
platforms provided for the
workers for the concreting
of the roof beams.
• Worker A was seen sitting on
the plywood placed on some
timbers at the opening of
the attic.
1. Roof beams
2. Attic level
3. The deceased was found at the fifth level
1. Deceased was seen resting here
2. Plywood
3. Opening
49

• The accident could have
occurred when Worker A was
resting on the plywood. The
plywood could have broken
and Worker A may have lost
his footing and fallen through
the opening. His head would
have hit the concrete floor
and the head injury could
have caused his death.
Root Cause Analysis
Evaluation of loss
Type of contact
• One worker killed
• Fall from height to lower level
Immediate cause(s) • Inadequate guards or barriers
• Inadequate or improper protective equipment
Basic cause(s)
Failure of SMS
• Improper motivation
• Lack of supervisory/management
job knowledge
• WSH practices and procedures
• WSH training and competence
Follow-up
The occupier was instructed to provide working platforms for
the workers for the concreting work at the roof.
Recommendations
Provide proper working platform.
Provide proper personal protective equipment.
Provide proper training.
50

CASE 20
FALL DUE TO AN UNSTABLE SCAFFOLD
Description of Accident
A worker was instructed to install
a special fixture called “bonding
bars” at the service duct area on
the fourth storey of a building
under construction.
An hour later, he was found to
have fallen together with a mobile
scaffold from the corridor of the
fourth storey of the building.
He landed on the ground floor.
He was sent to the hospital and
died on the same day.
Causes and Contributing
Factors
1. Tower scaffold at service duct area
2. Mobile scaffold
3. Parapet wall
4. Two caster wheels found on the
fourth storey
5. Uneven floor
• There were no eye-witnesses
to the accident. The worker
was probably using the
mobile scaffold when he
fell together with the scaffold
from the fourth storey to
the ground floor.
1. Tower scaffold
2. Unsecured decking
3. Bonding bars
51

• The following factors could
have contributed to the
accident:
i. The mobile scaffold erected
was not tied to the building
or other structures despite
the fact that its height (3.47m)
was more than three times
the lesser dimension of the
base (0.8m). In addition, it was
placed on an uneven floor.
The mobile scaffold would
have been unstable on such
a floor and any person using
it could cause it to topple.
ii. The mobile scaffold was
erected without any
supervision from a scaffold
supervisor to ensure that
it was properly erected
and stable.
Root Cause Analysis
Evaluation of loss
Type of contact
Immediate cause
Basic cause(s)
Failure of SMS
• One worker killed
• Fall from height to lower level
• Inadequate or improper protective equipment
• Inadequate leadership and/or supervision
• WSH practices and procedures
52

Follow-up
The occupier was instructed to implement a Permit-to-Work system
to control the use of tower and mobile scaffolds at the site.
Recommendations
Ensure proper inspection by a trained scaffold supervisor.
Secure mobile scaffold using ties if the scaffold is greater than
4m in height and is close to an opening.
Protect workers working close to an opening at a height greater
than 4m with fall arrest equipment.
53

CASE 21
FALL WHILE DISMANTLING A PLATFORM
Description of Accident
Worker A and his co-workers
were to dismantle a metal
platform erected on a scaffold
support. For this, they would have
to remove the clips that held the
pieces of metal formwork together
so as to take them apart.
Worker A was later found lying
on the ground beside the
scaffold support. He was taken
to the hospital where he passed
away on the same day.
1. The underside of the metal platform
that was to be dismantled
2. The metal clip holding adjacent pieces
of metal formwork together
Causes and Contributing
Factors
• The metal platform was about
4.5m above the ground.
• Worker A was last seen by the
foreman 7 to 8 minutes
prior to the accident. He was
doing some work on the ground
below the metal platform that
was to be dismantled.
1. The metal platform that was to
be dismantled
2. The scaffold support
3. The deceased was found lying here
after the accident
54

• Investigations revealed that
on the day of the accident,
a safe means of access or egress
from the metal platform,
such as a ladder ramp was not
provided on the scaffold.
• The accident probably
happened when Worker A
climbed up the scaffold
support to dismantle the metal
platform and lost his grip on
the scaffold frame and fell to
the ground.
Root Cause Analysis
Evaluation of loss
Type of contact
• One worker killed
• Fall from height to lower level
Immediate cause(s) • Inadequate or improper protective equipment
Basic cause(s)
Failure of SMS
• Inadequate engineering
• Inadequate work standards
• Hazard analysis and risk assessment
55

Follow-up
The occupier was instructed to implement the following safety
measures:
• Provide a working platform of at least 635cm width for use as
footing by workers dismantling the metal platforms.
• Provide a safe means of access, such as a ladder or an access ramp
with handrails for workers to gain access to the working platform
on the scaffold support.
• Workers must stand on the working platform and anchor
their safety belts to the scaffold frames while dismantling the
metal platform.
• The supervisor-in-charge is to brief the workers on the safety
aspects involved in the dismantling of the platform prior to the
commencement of work.
Recommendations
Provide proper access to the formwork level.
Develop and implement safe work procedures.
Ensure that the formwork supervisor is present during the
dismantling of formwork and its components.
Provide lifelines and fall protection for all work at heights.
Brief the workers on the safety aspects of working at heights prior
to the commencement of work. This should be done by the
supervisor-in-charge.
56

CASE 22
FALL OF A GONDOLA PLATFORM
Description of Accident
In the early morning, two workers
had started on the external
window and façade cleaning of
a building, using a permanent
gondola located at the rooftop
of the building.
About an hour later, the gondola
became jammed and the two
workers were left stranded in the
gondola between the 31st and
28th storey of the building.
About three hours later, the service
technicians from the gondola
supplier arrived on site. While
rectifying the fault, the platform of
the gondola together with the two
workers suddenly plummeted and
crashed onto the rooftop of the
podium at the fifth floor. One
worker died on the spot.
1. The gondola
1. The rooftop where the gondola crashed
Causes and Contributing
Factors
• The platform together with
the two workers plummeted
due to the fracturing of the
gearbox shaft holding the
emergency safety brake.
57

• The safety devices, hydraulic
pressure switch and electrical
thermal relay for the hoisting
motor were also found to be
incorrectly set. The wrong
setting allowed the gondola
to operate in an overloaded
condition without the power
being automatically cut off.
• Investigations revealed
that the gondola had earlier
experienced numerous
repetitive defects and
failures that resulted in the
non-functioning of the gondola.
However the gondola supplier
had not taken any measures
to establish the causes for the
recurring fault and rectify them.
• Whenever the technicians from
the gondola supplier were
called in, they would rectify by
resetting the over-speed device
and pumping the pressure up
so as to release the safety
brakes and render the gondola
mobile. This practice is contrary
to the instructions given by the
manufacturer. The system thus
deteriorated until the day of
the fatal accident.
• The occupier had not
registered the premises as a
factory even though the
external cleaning of windows
and façade was for a term
contract of two years and they
had been working for more
than two months.
Root Cause Analysis
Evaluation of loss
Type of contact
• One worker killed
• Fall from height to lower level
Immediate cause(s) • Defective tools, equipment or materials
Basic cause(s)
Failure of SMS
• Inadequate maintenance
• Inadequate tools and equipment
• Maintenance regime
58

Recommendations
Plan regular maintenance for the gondola.
Ensure the regular inspection of the mechanical and electrical
equipment by competent persons.
Ensure emergency and rescue procedures are strictly followed.
Avoid overloading equipment.
59

CASE 23
FALL FROM A SCAFFOLD
Description of Accident
60
Worker A and his co-workers were
working on a working platform on
a metal scaffold on the fourth
storey of a building. They were
preparing a beam for skim coating.
Worker A was wetting the beam
with a pail and was seen walking
backward while wetting the beam.
A few minutes later, Worker A was
found lying on the floor beside the
metal scaffold. He was taken to the
hospital where he passed away a
few days later.
Causes and Contributing
Factors
• Guardrails were provided on
the open sides of the working
platform. However guardrails
on both the left and right ends
of the working platform were
only secured on one side.
It was done this way so that the
guardrails could be swung open
for workers to get onto the
working platform when they
went up there to work.
1. The deceased was wetting this beam
prior to the accident
2. The guardrail on the right end of
the scaffold
3. The deceased probably fell from here
4. The working platform
5. The deceased landed here after
the accident
1. The deceased was wetting this beam
prior to the accident
2. The scaffold
3. The deceased landed here after
the accident

• No ladders or steps were
provided for workers to gain
access to the working platform.
• Both Worker A and the
co-worker who erected the
scaffold had not undergone
a training for scaffold erection.
The erection of the scaffold
was also not performed under
the supervision of a scaffold
supervisor.
• Worker A got up from one side
of the working platform. It is
probable that as he was walking
backwards while wetting the
beam, he failed to stop at the
end of the platform and fell to
the floor.
• It is also possible that the
deceased, after having finished
wetting the beam, was climbing
down the scaffold when he fell
to the floor.
Root Cause Analysis
Evaluation of loss
Type of contact
• One worker killed
• Fall from height to lower level
Immediate cause(s) • Inadequate guards or barriers
Basic cause(s)
Failure of SMS
• Inadequate leadership and/or supervision
• Hazard analysis and risk management
61

Follow-up
The occupier was instructed to implement the following safety
measures:
• All guardrails on the working platform to be secured.
• Steps must be provided on the scaffold for access to the working
platform or different levels of the scaffold.
• The erection of the scaffold is to be done by workers who have
undergone a course of training approved by the Chief Inspector.
• The erection must be supervised by a scaffold supervisor.
Recommendations
Secure end guardrails similar to the longitudinal guardrails.
Provide proper access such as ladders or steps.
62

Published in June 2008 by the
Workplace Safety and Health
Council in collaboration with
the Ministry of Manpower.
All rights reserved. This
publication may not be
reproduced or transmitted in
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information provided in this
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of printing. All cases shared in this
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purposes only. The learning points
for each case are not exhaustive
and should not be taken to
encapsulate all the responsibilities
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publication under the law. The
Workplace Safety and Health
Council does not accept any
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party for losses or damage arising
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