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CHEMICAL HAZARDS

Objective

By the end of the session, students should be able to :

� State specific characteristic of asbestos, mineral dust and lead

� Identify the routes of entry of asbestos, mineral dust, lead and organic solvents

� Explain the effects of asbestos, mineral dust, lead and organic solvents to human health

� Identify the legislation related to asbestos, mineral dust, lead and organic solvents.

� Explain the control measures

� Explain the health surveillance requirements

TOXICOKINETICS

� Movement of toxic materials

� Route of entry of toxic materials in to the human

body

� Outcome of toxic materials

- Distribution

- Metabolism

- Excretion

ROUTES OF ENTRY

Four methods

� Inhalation

� Ingestion – food intake and smoking

� Skin absorption

� Injection

� Eyes

The routes of entry may give indicators on the type of

monitoring and exposure control measures to be taken.

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FATE OF CHEMICALS

Distribution

� Process where the chemical and its metabolites are

distributed into he body

� Assist us to identifying the target organs of a chemical

and potential problems areas (Local effects and

Systemic effects)

� Facilitate medical surveillance of the specific organ

functions.

FATE OF CHEMICALS

Metabolism

� Process in which the absorbed chemical takes

another form

� This second form is called the metabolite

� Knowledge on the metabolite produced is important

for biological monitoring

FATE OF CHEMICALS

Excretion

� Process of disposing the absorbed material and

its metabolite from the body

� Excreted in a different manner (hair, nails, urine,

stools, breathing, sweating, saliva, tears)

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FACTORS INFLUENCE TOXITY

Chemical Characteristic

� Methods of exposure

� Physical properties

� Type of chemical

� Duration of exposure

� Concentration of exposure

� Effects of interaction between chemicals

FACTORS INFLUENCE TOXITY

Individual Characteristic

� Age

� Gender

� Allergies

� Genes

� Immunology status

� Food status

� Existing diseases

TYPES OF TOXIC EFFECTS

Various ways

� Duration of exposure (acute and chronic)

� Location of toxic effects (local and systemic)

� Occurrence of the effect after exposure (immediate

and delayed)

� Seriousness of the effect (reversible or irreversible)

� Organs affected (kidney, lungs, liver nervous

system etc)

� Specific effects (carcinogenic, allergies, mutagenic)

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TYPES OF TOXIC EFFECT

Duration of exposure (Acute and Chronic)

Acute exposure

� High dosage (chemical spillage or leakage, accidental)

� Acute effect / Short term effect (skin rashes/burns, sore

eyes etc)

Chronic exposure

� Low dosage

� Chronic effect / Long term effect (toxicity in nervous

system, cancer (cervix, breast, lung, kidney, prostate,

bone etc)

TYPES OF TOXIC EFFECT

LOCAL EFFECT

� Effect occurs at location of exposure

� eg - Chlorine (sore eyes, skin irritation)

- Acid (corrosive effect on skin)

SYSTEMIC EFFECT

� Occurs at a location away from place of chemical

entry

� eg - Organic solvent (narcosis effect)

TYPES OF TOXIC EFFECT

IMMEDIATE EFFECT

� Occurs immediately after exposure

� eg - 1,1,1 – trichloroethane (narcosis effect)

DELAYED EFFECT

� Toxic effect is only apparent after a certain duration

of exposure (workers are unaware)

� eg - Asbestosis – Lung cancer

� Its easier to identify the causing agent for immediate

effects compared with delayed effects

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TYPES OF TOXIC EFFECT

REVERSIBLE

� Toxic effects will lose its effect after exposure

(chlorine)

IRREVERSIBLE

� Toxic effects permanent even after exposure (Cancer)

� Irreversible effects are more dangerous than

reversible effects)

TYPES OF TOXIC EFFECT

SPECIFIC TOXIC EFFECTS

� Allergies to the respiratory system (asthma)

� Allergies to the skin

� Carcinogenic

� Mutagenic

� Teratogenic

TYPES OF TOXIC EFFECT

TARGETED ORGANS

� Lungs – Asbestosis (pheumoconiosis, lung cancer)

� Nervous system – Toluene (narcosis, nervous system

� Kidney – Cadmium (Kidney failure)

� Hematology – Benzene (leukamia)

� Knowledge of targeted organs is important for the

purpose of medical surveillance

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ASBESTOS

Specific Characteristic

� Is a generic name for magnesium silica that is

formulated through the natural process as long,

thin, crystalline fibres.

Two groups

� Fibrous serpentine called chrysotile or white asbestos

� Fibrous amphiboles called amosite, crocidolite,

anthophylite, tremolite and actinolite. Amosite also

known as brown asbestos

PROPERTIES AND USED

� Tensile strength, flexibility, chemical resistance, heat

resistance, thermal insulation and electrical insulation.

Can be mixed with cement and woven to reinforced

the products

� Chrysotile (white asbestos) strong and flexible.

� Resistance to high temperature

� Used in making suits, aprons, gloves, helmets

(protect from heat), fire blankets and flexible floor

tiles and roofing, friction products (brake shoes,

clutch plates and gaskets)

ASBESTOS USED INSIDE THE BUILDING

� Roofing

� Water tank

� Garage roof

� Wall panels

� Heating system

� Chimney

� Fire resistant paint

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METHODS OF EXPOSURE

Inhalation

� Fibre (type, size, dose)

� Duration of exposure

� Biological reaction of the respiratory systems

Ingestion - minor

RELATED LEGISLATION

� FMA (Asbestos) Regulations 1986

- Permissible Exposure Limit, Exposure monitoring,

Control of exposure and control measures

� OSAH (Use and Standards of Exposure of Chemicals

Hazardous to Health) Regulations 2000

- PEL, Risk Assessment, Health surveillance and

control measures

HEALTH HAZARDS

Caused by their :

� Fibrous nature

� Durability in the lungs

ASBESTOSIS

� Earliest discovered from exposure to high

concentration of airborne asbestos over several years

� Amongst coal workers and those expose to asbestos

� Asbestos inhaled deposited in the deep lung resulting

in a thickening of the alveoli walls due to presence

of the fibre (alveoli affected)

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HEALTH HAZARDS

PLEURAL PLAQUES

� Benign condition involving pleural (membrane

covering the lungs) thickening

� Indicative of asbestos exposure

MESOTHELIOMA

Rare cancer occurs in the pleural or peritoneum (the membrane covering the bowel cavity)

Associated with exposure to crocidolite and armosite

15 to 50 years to developed

CONTROL MEASURES

Elimination

Prohibition of crociodolite

Minimise exposure

� Work processes and practices

� Engineering control (LEV) or (Dust collector)

� PPE

HEALTH SURVEILLANCE

Medical Assessment (by OHD)

� History (medical, occupational, smoking)

� Clinical examination

� Chest x-ray

� Lung function test

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MINERAL DUST

APPLICATION

� All factories where there are processes using

mineral dust

Mineral Dust Process

� Manufacturing process involving use of mineral dust

PROHIBITION

� Sand blasting process shall not be used in any

factory unless with written approval from Chief

Inspector

MINERAL DUST

SPECIFIC CHARACTERISTIC

� Mineral dust (silica, kaolin, quartz etc)

� Silica (silicon dioxide)

- Free form (quartz, cristobalite, tridymite)

- Mixture (silicate) : asbestos, kaolin

METHODS OF EXPOSURE

Inhalation

Risk depends on :-

� Exposure

� Size

� Type of mineral dust

� Intensity of mineral dust in breathing zone

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OCCUPATION AT RISK

� Works involving rocks containing silica

� Ceramic

� Glass manufacturing

� Cement

� Mining

� Quarry

� Sand blasting and sand preparation

RELATED LEGISLATION

� FMA (Mineral Dust) Regulations 1989

� OSAH (Use and Standards of Exposure of Chemicals

Hazardous to Health) regulations 2000

HEALTH EFFECTS

� Pneumoconiosis (Fibrosis of the lung due to

inhalation of mineral dust)

� Lung cancer

� Lung failure

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CAUSE AGENT

Pneumoconiosis

AGENT SPECIFIC AGENT

Crystalline silica Silicosis

Coal dust Coal miners pneumoconiosis

Mineral talc Talcosis

Ferum oxide Siderrosis

Tin oxide Stannosis

CONTROL MEASURES

� Elimination

� Substitution

� Engineering Control (Water spraying, LEV)

� Work Procedures

- Cleanliness

- Hygiene

- Changing Room

- Warning signals

� PPE

- Respirator

- Clothing

- Correct type, suitable, good maintenance, hygiene

HEALTH SURVEILLANCE

� Exposure Monitoring

� Health Surveillance (OHD)

- History

- Clinical examination

- Chest x-ray

- Lung function test

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FMA (MINERAL DUST) REGULATIONS 1989

PEL

Dust that contain Silica <1% Silica :

Worker exposure should not exceed the average concentration for a duration of 8 hours :

5 mg/m3 – respirable dust

10 mg/m3 – total dust

0.05 mg/m3 – respirable cristobalite/trydymite

0.10 mg/m3 – respirable quartz

FMA (MINERAL DUST) REGULATIONS 198

PPE

If > PEL, provide :

� Clothing that covers the whole body

� Gloves, hats, shoes

� Face shields, goggle etc

� The employer is responsible to provide facilities for

the hygiene and disposal of clothing and equipment

LEAD

APPLICATION

� All factories processes where lead is used

� Does not apply on construction sites or works

of engineering construction

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FMA (LEAD) REGULATIONS 1986

PEL

� 150 mg/m3 / 8 hour average

� Action level = 75 ug/m3 / 8 hour average

HYGIENE PRACTICES AND FACILITIES

ASBESTOS, MINERAL DUST AND LEAD

EXPOSURE

� Clean floor from contaminants

� Cleaning should be using vacuum cleaner

� Use of compressed air is prohibited

(Lead and Mineral Dust Regulations)

HYGIENE PRACTICES AND FACILITIES

ASBESTOS, MINERAL DUST AND LEAD EXPOSURE

Changing room, Lockers and Showers

� Lockers for daily wear

� Separate lockers for protective clothing and

respiratory equipments

� Changing rooms (asbestos process and lead only)

� Showers (asbestos process and lead only)

� Separate dining facilities from work areas (lead)

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MEDICAL SURVEILLANCE

LEAD EXPOSURE

If exposed > 30 days/year

Frequency of blood lead test, every :

6 months

3 month if 40-60ug/100g blood

1 month if 60-80ug/100g blood

1 month if in period of medical transfer

1 month for women who are able to conceive

MEDICAL SURVEILLANCE

LEAD EXPOSURE

� Medical surveillance is conducted :

� Every 1 year if <> 40ug/100g blood

� Before being assigned to a work area where air concentration <. Action level

� There are signs of symptoms of poisoning

� Every worker in the medical transfer if required by a

doctor

MEDICAL SURVEILLANCe

ASBESTOS PROCESS

� Workers working in an area where there is

asbestos exposure, whether continuous

or intermittent

� In the period of 30 days from the first day of work

� Frequency (not exceeding 2 yrs)

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MEDICAL SURVEILLANCE

MINERAL DUST EXPOSURE

� If exposed > action level

Frequency of testing :

�Every 2 years

�Exposed worker > action level

�Every year

�Workers experiencing early signs of pneumoconiosis

MEDICAL REMOVAL

LEAD EXPOSURE

� Worker should be removed/transferred

� If blood lead tests show

- 80ug/100g blood

- Average 3 latest test <> 73ug/100g blood

- <> 40ug/100g blood for women who are able

to conceive

� Health of the worker may be affected based

on results/medical opinion

MEDICAL REMOVAL

ASBESTOS PROCESS

Worker should be removed / transferred if results or medical opinion shows any early indications of asbestos related diseases.

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RECORD KEEPING

� Monitoring records

As long as the worker is in service – asbestos, mineral dust, noise exposure

� Medical Surveillance records

As long as the worker is in service – leas, asbestos exposure

5 years – noise exposure

25 years – mineral dust

Records are kept by employer/doctor

� Medical removal records

As long as the worker is in service - lead

Thank you……..