Session 18 Workplace Environment and Occupational Hygiene 1 OSH5063EP(PRS3607) Workplace and Work Equipment Hazard
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Session 18
Workplace Environment and
Occupational Hygiene
1
OSH5063EP(PRS3607)
Workplace and Work Equipment Hazard
2
Introduction
In some part of the world occupational hygiene is
also known as industrial hygiene.
Occupational Hygiene, is often defined as:
“The recognition, evaluation and control of
workplace hazards”
3
Introduction
Occupational hygiene is the application of scientific,
technological and managerial principles to protect
the health or workers, and of those outside the
workplace, by preventing or reducing risk due to
chemical, physical and biological agents.
4
Introduction
An effective occupational hygienist has scientific
skills to enable the thorough analysis of the
workplace, technological skills that may aid in the
design or control of hazards, and managerial skills
to enable idea to be communicated, and
successfully implemented.
5
Introduction
The World Health Organization definition of health
is :
“ Not merely the absence of disease but a state of
complete physical, mental and social well-being”
This definition acknowledges that optimal human
wellbeing is multifaceted and can be influenced in
many ways.
6
Introduction
People at work encounter four basic classes of
health hazard:
Chemical
Physical
Biological
Ergonomic / Psychosocial
7
Physical health hazards
Examples of physical health hazards include:
Noise,
vibration,
heat,
light,
lionizing radiation,
pressure,
ultraviolet light, etc.
8
Chemical health hazards
Examples of chemical health hazards include:
Dusts
Vapours
Fumes
Gases
mists etc.
(100 000 chemicals are believed to be in common
use in the UK at present)
9
Biological health hazards
Examples of biological health hazards include:
Insects,
mites,
yeasts,
bacteria,
viruses,
proteolytic enzymes.
10
Ergonomic / Psychosocial health
hazards
Examples of ergonomic / psychosocial health
hazards include:
Personal-task interaction, e.g. body position in
relation to use of machine;
Harmful repetitive work.
Exposure to harmful psychological stress at work.
11
Physical causes
Example includes:
Heat – heat cataract, heat stroke.
Noise – noise-induced hearing loss.
Vibration – vibration-induced white finger.
Radiation – radiation sickness, burns, arc eye.
Dust – silicosis, coal worker’s pneumoconiosis.
Pressures – decompression sickness.
12
Chemical causes
Example includes:
Acids and alkalis – dermatitis.
Metals – lead and mercury poisoning.
Non-metals – arsenic and phosphorus poisoning.
Gases – carbon monoxide poisoning, arsine
poisoning.
Organic compounds – occupational cancers.
Dust – mercury poisoning.
13
Biological causes
Example includes:
Animal-borne – anthrax brucellosis, glanders fever.
Human-borne – viral hepatitis.
Vegetable-borne – asergillosis (farmer’s lung).
14
Ergonomic causes
Example includes:
Job movements – cramp (in relation to handwriting
or typewriting)
Friction and pressure – traumatic inflammation of
the tendons or associated tendon sheaths of the
hand or forearm.
15
Avoiding potential risks
The occupational hygienist or occupational health
practitioner can make a significant contribution to
the planning and design of work layouts, and to
considering the ergonomic aspects of jobs and the
potential for fatigue amongst workers.
The effects of shift working, long hours of work and
the physical and mental effects of repetitive tasks
would be taken into account in any assessment of
risks involved.
16
Health Impact Assessment
HIA is a process by which the potential effects on
the health of individuals or communities of a
proposed development or activity can be assessed.
The assessment includes the risks that people may
face either directly or indirectly from various
environmental conditions or hazards.
17
Health Impact Assessment
Identification
Evaluation
Measurement
Control Measure
18
Identification
Identification of health hazards:
Potential Health hazards
Raw materials, products and by-products
Process and operations
Records of accidents and diseases
Site inspection and survey
Sampling
19
Potential Hazards
Classification of Potential Hazards
Chemical hazards
Biological hazards
Physical hazards
Ergonomic hazards
Psychosocial factors
20
Potential Hazards
Nature of Potential Hazards
Particulate contaminants
– dust, fumes, mists, aerosols, fibers, etc
Gas and Vapor
21
Process and Operation
The materials involved
Points of materials entry and exit
Normal operating procedures
Potentials hazards
The potentials for emissions into the atmosphere
The potential for exposure
Arrangements for engineering controls
The use of PPE
22
Site inspection and survey
Site Inspection
Senses of smell, hearing and touching
Observation of abnormal functions and practices
Survey
Communication with workers
Survey of health problem
Measurement Techniques
Based on the nature of hazards and the routes of
environment contact with the workers
Air sampling- concentration of toxic particulates,
gases and vapors that worker may inhale
Skin wipes- the degree of skin contact with toxic
materials that may penetrate the skin
Noise dosimeters –record work-place noise levels
24
Measurement
Grab sampling
Grab sampling is adopted in the context of stain
detector tubes. This involved taking a sample of air
over a relatively short period of time in order to
measure the concentration of a contaminant.
It is a quick, simple, economical and versatile
technique.
25
Measurement
Long-term sampling
This involves sampling air for several hours or even
the whole work shift.
The air sampling may be carried out in the worker’s
breathing zone or at a selected point or points in the
workplace.
Results give the average levels of contaminant across
the sample period.
26
Measurement
This long-term sampling approach is used for the
monitoring of gas and vapour contaminants and dust
and fibre aerosols.
Long-term sampling methods are generally reliable,
versatile and accurate, being widely used by
occupational hygienists in checking the compliance
with hygiene standard.
27
Measurement
Fibre monitoring
In the measurement of airborne asbestos fibres the
collection device is a membrane filter within an
imprinted grid.
The airborne concentration of countable fibres can be
measured using phase contrast microscopy.
This technique measures only a proportion of the total
number of fibres present.
28
Measurement
Direct monitoring instruments
A wide range of instruments are used in the detection
of gases, vapours and dusts. This devices make a
quantitative analysis giving a real-time display of
contaminant level on a meter, chart recorder, data
logger or other display equipment.
Direct monitoring is particularly useful where there is
a need to have immediate readings of contaminant
levels, for example in the case of fast acting chemicals.
29
Measurement
It is also useful for identifying periods of peak
concentration during the work cycle or work shift so
that a control strategy can be developed.
30
Measurement
Oxygen analysers
Deficiency of oxygen in the atmosphere of confined
spaces is often experienced in industry.
Before entering a confined space, a check must be
made on the oxygen content of the atmosphere
throughout the working area.
31
32
Evaluation
When a health hazard in the workplace has been
identified it is necessary to assess the consequent
risk, interpret this against a risk tolerability standard
and where appropriate apply further prevention and
control measures.
Evaluation
Standards
World Health Organization
International Organization for Standardization
European Community
American Conference of Governmental Industrial
Hygienists
American Industrial Hygiene Association
National Institute for Occupational Safety and Health
34
Control Measures
The general control strategy should include
consideration of:
◦ Specification
◦ Substitution
◦ Segregation
◦ Local exhaust ventilation
◦ General dilution ventilation
◦ Good housekeeping and personal hygiene
◦ Reduced time exposure
◦ Personal protection
35
Specification
The design of a new plant or process is the ideal
stage to incorporate hazard prevention and control
features, e.g. limiting the quantities of toxic
materials handled, the provision of remote handling
facilities, utilizing noise control features in the
design and layout of new machinery etc.
Including safety features at the design stage will be
much less costly than having to add them later.
36
Substitution
This involves the substitution of materials or
operations in a process by safer alternatives.
A toxic material may be replaced by another less
harmful substance or in another context something
less flammable.
Alternatively the process itself may be changed to
improve working conditions with a possible benefit
of increased efficiency as well.
37
Segregation
If a substance or process cannot be eliminated,
another strategy is to enclose it completely to
prevent the spread of contamination.
This may be by means of a physical barrier, e.g.
acoustic booth surrounding a noisy machine or
handling toxic substance in a glove box, etc.
Relocation of a process to an isolated area is
another possibility that reduces the number
exposed to the hazards.
38
Local extract ventilation
Where it is not practicable to enclose the process
totally, other steps must be taken to contain
contaminants. This can be achieved by removing
vapours, gases, dusts and fumes etc. by means of a
local extract ventilation system.
The local extract ventilation system traps the
contaminant close to its source and removes it so
that nearby workers are not exposed to harmful
concentrations.
39
Dilution ventilation
Sometimes it is not possible to extract the
contaminant close to its source of origin and
dilution ventilation may be used under the following
circumstance where there is:
Small quantity of contaminant.
Uniform evolution
Low toxicity material
40
Dilution ventilation
Dilution ventilation utilizes natural convention
through open door, windows, roof ventilators or
assisted by ventilation by fans or blowers.
41
Personal hygiene and good
housekeeping
Personal hygiene and good housekeeping have an
important role in the protection of the health of
people at work.
Immediate clean-up of spillages, safe disposal of
waste and the regular cleaning of work stations
prevents the spread of contaminants.
Adequate washing and eating facilities should be
provided with instruction for workers.
42
Personal protection
Making the workplace safe should be the first
consideration but if it is not possible to reduce risk
sufficiently by the abovementioned methods the
worker may need to be protected from the
environment by the use of personal protective
equipment (PPE).
43
Personal protection
PPE may be broadly divided as follows:
Hearing protection
Respiratory protection
Eye and face protection
Protective clothing
Skin protection
44
45
Personal protection
PPE have a serious limitation in that they do
nothing to attenuate the hazard at source, so that if
they fail and it is not noticed the user’s protection is
reduced and the risk the person faces increase
correspondingly.
46
Placing people in suitable work
Pre-employment medical examination has been
common practice for many years.
Pre-employment screening activities now include
not only an assessment of general fitness for the
job but specific aspects of it such as vision
screening of drivers, VDU operators and people
engaged in fine assembly work, the assessment of
disability levels where heavy work is involved,
certain tests for suitability as food handlers.
47
Health surveillance
Health surveillance concentrates on two main
groups of workers:
a. Those at risk of developing further ill-health or disability
by virtue of their present state of health, e.g. people
exposed to excessive noise levels; and
b. Those actually or potentially at risk by virtue of the type
of work they undertake during their employment, e.g.
radiation workers.
48
Health surveillance
Health surveillance usually takes the form of
ongoing health examination at predetermined
intervals of, say, 6 or 12 months according to the
degree of risk involved.
Such a system allows for early detection of
evidence of occupational disease and for its early
treatment.
49
Monitoring
Primary monitoring is concerned largely with the
clinical observation of sick people who may seek
treatment or advice on their condition.
Such observation will identify new risks which were
previously not considered.
50
Monitoring
Secondary monitoring is directed at controlling the
hazards to health which have already been
recognized.
Examples: exposure to noise, using vibratory hand
tools, etc.
51
Counselling
Counselling, carried out by a trained occupational
physician or occupational health nurse, is perhaps
the most significant component of occupational
health practice.
The counselling may take two forms:
Counselling on health-related matters
Counselling on personal, social and emotional
problems.
52
Counselling
Most people, at some time in their lives, have social
and emotional problems, which may be caused by
works, and over a period of time, develop a high
state of stress.
The results in an ability to concentrate for long
periods, fatigue, frustration and absence from work.
The availability of a sympathetic ear, independent of
organizational controls, can assist the individual to
terms with such problem more easily.
53
Environmental control and
occupational hygiene
Control of the working environment and the
environment outside the workplace are important
components of occupational health and hygiene
practice.
The employer must provide a safe working
environment by recognition, measurement,
evaluation and control of long-term health hazards.
Q&A
54
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