session 18 workplace environment and occupational hygiene · personal hygiene and good housekeeping...

Session 18

Workplace Environment and

Occupational Hygiene

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OSH5063EP(PRS3607)

Workplace and Work Equipment Hazard

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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”

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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.

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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.

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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.

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Introduction

People at work encounter four basic classes of

health hazard:

Chemical

Physical

Biological

Ergonomic / Psychosocial

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Physical health hazards

Examples of physical health hazards include:

Noise,

vibration,

heat,

light,

lionizing radiation,

pressure,

ultraviolet light, etc.

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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)

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Biological health hazards

Examples of biological health hazards include:

Insects,

mites,

yeasts,

bacteria,

viruses,

proteolytic enzymes.

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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.

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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.

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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.

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Biological causes

Example includes:

Animal-borne – anthrax brucellosis, glanders fever.

Human-borne – viral hepatitis.

Vegetable-borne – asergillosis (farmer’s lung).

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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.

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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.

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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.

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Health Impact Assessment

Identification

Evaluation

Measurement

Control Measure

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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

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Potential Hazards

Classification of Potential Hazards

Chemical hazards

Biological hazards

Physical hazards

Ergonomic hazards

Psychosocial factors

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Potential Hazards

Nature of Potential Hazards

Particulate contaminants

– dust, fumes, mists, aerosols, fibers, etc

Gas and Vapor

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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

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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

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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

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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

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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.

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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.

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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.

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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.

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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

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Dilution ventilation

Dilution ventilation utilizes natural convention

through open door, windows, roof ventilators or

assisted by ventilation by fans or blowers.

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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.

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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).

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Personal protection

PPE may be broadly divided as follows:

Hearing protection

Respiratory protection

Eye and face protection

Protective clothing

Skin protection

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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

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