Occupational Hazard
``Source or situation with a potential for
harm in terms of injury or ill health, damage
to property, damage to the workplace
environment, or a combination of these``
Occupational Health Hazards
Types
Âť Physical
Âť Chemical
Âť Biological
Âť Mechanical
Âť Psychosocial
Diseases due to Physical Agents
Heat â Exhaustion, Syncope, Cramps, burns, Prickly
Cold â Frost bite
Light â Occupational Cataract, Illumination Atmospheric-pressure â Caisson disease, explosion
Noise â Occupational deafness
Radiation â Cancer, Leukemia, aplastic anemia
Electricity â Burns, Shocks
Heat Illness ⢠Predisposing Factors
â Physical activityâ Extremes of age, poor physical condition, fatigueâ Excessive clothingâ Dehydrationâ Cardiovascular diseaseâ Skin disordersâ Obesityâ Drugs
⢠Phenothiazines, Anticholinergics, Diuretics, Amphetamines, Cocaine, MAOIs
Chemical Hazards⢠Routes of entry â Inhalation (main route of entry),
Ingestion, skin absorption⢠Chemical agents:
â Metals - Lead, As, Hg, Cd, Ni , Coâ Aromatic Hydrocarbons - Benzene, Toluene,
Phenol â Aliphatic Hydrocarbons - Methyl alcohol â Gases - Simple asphyxiants : N2, CH4, CO2
Chemical asphyxiants : CO, H2S, HCN
Irritant gases : Ammonia, SO2, Cl2
TLV (Threshold Limit Value)
âTime-weighted average concentration for a normal 8-hour working day and a 40-hour working week, to which nearly all workers may be repeatedly exposed day after day, without adverse effectâ
Biological Hazards
⢠Bacteria â Tetanus, Tuberculosis, Anthrax, Brucellosis (Milkmen), Gonorrhea
⢠Virus â Hepatitis, HIV
⢠Protozoal & Parasitic â Malaria, Hookworms, Hydatid (Dog-handlers), tapeworms
⢠Fungi (Agri-workers) â Tinea-infections, Psittacosis, Coccidiomycosis, Ornithosis
Mechanical Hazards
⢠Injuries â Falls, cuts, abrasions, concussions, contusions
⢠Ergonomic Disorders â Musculo-skeletal disorders(MSDs), Cumulative-trauma-Disorders (CTDs)
⢠Ergonomics â Adjustment of Man & Machine
⢠Ergo-friendly tools â Tools which reduce the stresses or problems resulting in CTDâs / MSDâs.)
Psychosocial Hazards
⢠Lack of job satisfaction, insecurity, poor interpersonal relations, work pressure, ambiguity
⢠Psychological & behavioral changes â hostility, aggressiveness, anxiety, depression, alcoholism, drug addiction, sickness absenteeism
⢠Psychosomatic disorders â Hypertension, headache, body-ache, peptic ulcers, asthma, diabetes, heart disorders
Occupational Lung Diseases(Pneumoconiosis)
Pneumoconiosis is a group of lung diseases which result from inhalation of dust in certain occupations.
Letâs consider a coal mine which contains approximately 800-1000 particles/ml, will inhale between 100 to 150 grams of dust yearly. Of the dust inhaled, about 1 to 10 grams is deposited in the alveoli, but only about 0.5 g is permanently retained. After 40 years of working, this amounts to 20 grams, half as much as the weight of the normal dried lung.
Classification of Pneumoconiosis
â˘Benign Pneumoconiosis
â˘Simple Pneumoconiosis
â˘Complicated Pneumoconiosis
Benign Pneumoconiosis
⢠Dust could not Produce fibrosis⢠Examples include:
â Baritosis: pure Barium sulphate and oxideâ Siderosis: ferric oxideâ Titanosis: titanium oxideâ Chalkosis: calcium salts
Simple Pneumoconiosis
⢠Inhaled dust causes only minimal fibrosis⢠Examples:
â Silicatosis: inhalation of complex silicates (not free silica) e.g., clays
â Vegetable dust pneumoconiosis:⢠Mill fever: organic dust⢠Byssinosis: cotton dust⢠Farmerâs lung: grain dust⢠Bagassosis: sugar-cane fibres
Complicated Pneumoconiosis
⢠Produce Progressive Massive Fibrosis⢠Examples:
â Silicosis: inhalation of free crystalline Silica SiO2â Asbestosis: inhalation of fibrous tri-magnesium
silicatesâ Talcosis: inhalation of talc powderâ Coal minerâs pneumoconiosis: inhalation of coal
dust
⢠Nature and chemical composition⢠Size of dust particles⢠Concentration of dust in atmosphere⢠Duration of exposure⢠Individual susceptibility
Factors affecting the development of disease (by depositing dust particles in the resp system)
Nature and Chemical Composition
Inorganic dustse.g. Silica, Asbestos
⢠Massive progressive fibrous reaction in the lung
Organic dustse.g. Cotton dust, grain
dust, sugar-cane fiber⢠Asthma bronchitis, non
distinguishable
Size of Dust Particles⢠10-5 Ο: Removed from upper respiratory tract⢠5-3 Ο :Deposited in the mid respiratory tract⢠3-1 Ο:Deposited directly in the alveoli⢠< 1 ¾: Move in and out of the alveoli with air,
â may be deposited in alveolar wall by impaction, or being caught by alveolar movement
Size of Dust
10- 5 Îź Upper Respiratory tract
5 - 3 Îź Mid respiratory tract
3 - 1 Îź Alveoli
Study of some common Pneumoconiosis
SilicosisPathological condition of the lung due to inhalation of particulate matter containing free silica or uncombined silica (SiO2)
⢠Permanent scarring of the lungs caused by inhaling silica (quartz, SiO2) dust
⢠Slowly progressive, nodular, fibrosing
pneumoconiosis
Thickened pleura
Fibrosis
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Common Occupations with Exposure to Silica
⢠Mines⢠Porcelain⢠Sand bricks industry⢠Glass industry⢠Gun industry ⢠Grinding of metals using sand stone
Pathology
Fibrotic nodules develop by a particular process in which fibrous tissue is laid down in concentric rings around a central core of silica particles as an onion
Manifestations
Symptoms⢠shortness of breath
while exercising ⢠fever ⢠occasional bluish skin at
ear lobes or lips ⢠fatigue ⢠loss of appetite
3 Types of Silicosis(based on amount of exposure and length of time)
Chronic⢠occurs after 10 or more years of mild overexposure to
silica ⢠the most common of all types ⢠may go undetected for years Accelerated⢠develops between 5 and 10 years of moderate
overexposure Acute⢠develops within weeks up to five years due to
breathing very large amounts of silica
⢠Diffuse fibrosis of the lung parenchyma
⢠Asbestos fibers, highly resistant to heat, acids and chemicals
⢠Widely used in industries⢠Banned from use globally since
1973 because it is highly carcinogenic
⢠Diffuse fibrosis of the lung parenchyma
⢠Asbestos fibers, highly resistant to heat, acids and chemicals
⢠Widely used in industries⢠Banned from use globally since
1973 because it is highly carcinogenic
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Asbestosis
⢠Parenchymal lung fibrosis with or without pleural involvement due to inhalation of asbestos fibres.
⢠More dangerous than silicosis as it predisposes to bronchogenic carcinomabronchogenic carcinoma and mesotheliomamesothelioma of the pleura and peritoneum
Complications
⢠Bronchogenic carcinoma⢠Mesothelioma
Prevention of Pneumoconiosis
Medical measures
⢠Pre-employment examination⢠Periodic examination
Conducted every yearInclude LFTIf susceptible worker (significant effect
across shift after few month of exposure) should be transferred to other job
⢠Health education ⢠Nutrition⢠Prohibition of smoking
Engineering Controls ⢠Designing-building, Work station⢠Good Housekeeping, wet mopping⢠Ventilation⢠Mechanization, Vacuum cleaning⢠Substitution⢠Enclosure machine dust⢠Isolation/Segregation⢠Local Exhaust Ventilation⢠Personal Protective Devices⢠Work Environment Monitoring⢠Statistical Monitoring