chemical hazards hazards.pdf · fibrous serpentine called chrysotile or white asbestos fibrous...
TRANSCRIPT
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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……..