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

» Physical

» Chemical

» Biological

» Mechanical

» Psychosocial

Diseases due to Physical Agents

Heat – Exhaustion, Syncope, Cramps, burns, Prickly

Cold – Frost bite

Light – Occupational Cataract, Illumination Atmospheric-pressure – Caisson disease, explosion

Noise – Occupational deafness

Radiation – Cancer, Leukemia, aplastic anemia

Electricity – Burns, Shocks

Heat Illness • Predisposing Factors

– Physical activity– Extremes of age, poor physical condition, fatigue– Excessive clothing– Dehydration– Cardiovascular disease– Skin disorders– Obesity– Drugs

• Phenothiazines, Anticholinergics, Diuretics, Amphetamines, Cocaine, MAOIs

Chemical Hazards• Routes of entry – Inhalation (main route of entry),

Ingestion, skin absorption• Chemical agents:

– Metals - Lead, As, Hg, Cd, Ni , Co– Aromatic Hydrocarbons - Benzene, Toluene,

Phenol – Aliphatic Hydrocarbons - Methyl alcohol – Gases - Simple asphyxiants : N2, CH4, CO2

Chemical asphyxiants : CO, H2S, HCN

Irritant gases : Ammonia, SO2, Cl2

TLV (Threshold Limit Value)

“Time-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 effect”

Biological Hazards

• Bacteria – Tetanus, Tuberculosis, Anthrax, Brucellosis (Milkmen), Gonorrhea

• Virus – Hepatitis, HIV

• Protozoal & Parasitic – Malaria, Hookworms, Hydatid (Dog-handlers), tapeworms

• Fungi (Agri-workers) – Tinea-infections, Psittacosis, Coccidiomycosis, Ornithosis

Mechanical Hazards

• Injuries – Falls, cuts, abrasions, concussions, contusions

• Ergonomic Disorders – Musculo-skeletal disorders(MSDs), Cumulative-trauma-Disorders (CTDs)

• Ergonomics – Adjustment of Man & Machine

• Ergo-friendly tools – Tools which reduce the stresses or problems resulting in CTD’s / MSD’s.)

Psychosocial Hazards

• Lack of job satisfaction, insecurity, poor interpersonal relations, work pressure, ambiguity

• Psychological & behavioral changes – hostility, aggressiveness, anxiety, depression, alcoholism, drug addiction, sickness absenteeism

• Psychosomatic disorders – 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.

Let’s 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

•Benign Pneumoconiosis

•Simple Pneumoconiosis

•Complicated Pneumoconiosis

Benign Pneumoconiosis

• Dust could not Produce fibrosis• Examples include:

– Baritosis: pure Barium sulphate and oxide– Siderosis: ferric oxide– Titanosis: titanium oxide– Chalkosis: calcium salts

Simple Pneumoconiosis

• Inhaled dust causes only minimal fibrosis• Examples:

– Silicatosis: inhalation of complex silicates (not free silica) e.g., clays

– Vegetable dust pneumoconiosis:• Mill fever: organic dust• Byssinosis: cotton dust• Farmer’s lung: grain dust• Bagassosis: sugar-cane fibres

Complicated Pneumoconiosis

• Produce Progressive Massive Fibrosis• Examples:

– Silicosis: inhalation of free crystalline Silica SiO2– Asbestosis: inhalation of fibrous tri-magnesium

silicates– Talcosis: inhalation of talc powder– Coal miner’s 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 μ: Removed from upper respiratory tract• 5-3 μ :Deposited in the mid respiratory tract• 3-1 μ:Deposited directly in the alveoli• < 1 µ: Move in and out of the alveoli with air,

– may be deposited in alveolar wall by impaction, or being caught by alveolar movement

Size of Dust

10- 5 μ Upper Respiratory tract

5 - 3 μ Mid respiratory tract

3 - 1 μ 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