Occupational Cancers - Park's PSM

Historical Note

Types of Occupational Cancers

1. Skin Cancer

• Most common - nearly 75% of all occupational cancers are skin cancers
• Causative agents: Coal tar, X-rays, certain oils and dyes (mineral oil, pitch, tar, and related compounds)
• Occupations at risk:
  • Gas workers
  • Coke oven workers
  • Tar distillers
  • Oil refiners
  • Dye-stuff makers
  • Road makers

2. Lung Cancer

• Causative agents:
  • Proved carcinogens: Nickel, chromates, asbestos, coal tar (3-4 benzpyrene), radioactive substances, cigarette smoking
  • Suspected carcinogens: Arsenic, beryllium, isopropyl oil
• Occupations at risk:
  • Gas industry
  • Asbestos industry
  • Nickel and chromium work
  • Arsenic roasting plants
  • Mining of radioactive substances (e.g., uranium)
• More than 9/10 lung cancers are attributed to tobacco smoking, air pollution, and occupational exposure combined

3. Cancer of the Bladder

• First noted in the aniline industry in 1895; later noted in the rubber industry
• Mechanism: Caused by aromatic amines, which are metabolized in the body and excreted in urine (hence concentrating in the bladder)
• Bladder carcinogens:
  • Beta-naphthylamine
  • Benzidine
  • Para-amino-diphenyl
  • Auramine
  • Magenta
• Industries associated:
  • Dye-stuffs and dyeing industry
  • Rubber industry
  • Gas industry
  • Electric cable industry

4. Leukaemia

• Causative agents:
  • Benzol (benzene) - a dangerous chemical used as a solvent in many industries
  • Roentgen rays (X-rays)
  • Radioactive substances
• Key point: Leukaemia may appear long after exposure has ceased

Characteristics of Occupational Cancer (Important for MCQs)

1. They appear after prolonged exposure
2. The period between exposure and development of disease may be as long as 10 to 25 years (latent period)
3. The disease may develop even after cessation of exposure
4. The average age of incidence is earlier than cancer in general
5. The localization of tumours is remarkably constant in any one occupation

Control of Occupational/Industrial Cancer

1. Elimination or control of industrial carcinogens (technical measures: closed systems, exclusion of carcinogens)
2. Medical examinations (pre-employment and periodic)
3. Inspection of factories
4. Notification
5. Licensing of establishments
6. Personal hygiene measures
7. Education of workers and management
8. Research

Quick Reference Table

Plumbism (Lead Poisoning / Saturnism / Saturnine Poisoning)

Sources of Exposure / Occupations at Risk

• Manufacture of white lead, lead paint
• Smelting, oxyacetylene ship breaking
• Diamond cutting, file making, car welding & polishing
• Printing (type-setting)

• Battery work, plumbing, glazing pottery
• Paint ingestion (children licking toys, walls)
• Food in tinned vessels, ghee in brass/copper-lined tins
• Drinking water from lead pipes/cisterns
• Hair dyes and cosmetics containing lead

• Only organic lead compounds (especially tetraethyl lead)
• Inorganic compounds are NOT absorbed through intact skin

Mechanism of Toxicity

• Combines with SH-groups of enzymes involved in porphyrin synthesis and carbohydrate metabolism
• Inhibits delta-aminolevulinic acid dehydratase (ALAD) and ferrochelatase - blocking haem synthesis
• Inhibits 5-pyrimidine nucleotidase - causing accumulation of RNA degradation products in RBCs (basophilic stippling)
• Affects membrane permeability - causing potassium leakage from erythrocytes

Blood level 70 μg/100 ml is associated with clinical symptoms. Chronic poisoning results from daily intake of 1-2 mg of lead.

Clinical Features of Chronic Lead Poisoning (Plumbism)

1. Facial Pallor

• Earliest and most consistent sign
• Particularly around the mouth
• Due to vasospasm

2. Anaemia

• Hypochromic anaemia with:
  • Polychromasia
  • Punctate basophilia (basophilic stippling) - dark blue pinhead spots in RBC cytoplasm
  • Reticulocytosis
  • Poikilocytosis, anisocytosis
  • Nucleated RBCs (sideroblasts)
  • Increased mononuclear cells, decreased PMNs and platelets
• Porphyrins excreted in urine: up to 500 μg/day

3. Lead Line (Burtonian Line)

• Stippled bluish-black line on gums at the junction with teeth
• Seen in 50-70% of cases
• Due to subepithelial deposition of lead sulphide (formed by action of H₂S from decomposed food)
• Appears within a week of exposure, especially near dirty/carious teeth, upper jaw
• Also seen (less specifically) in: mercury, copper, bismuth, iron, silver poisoning

4. Colic and Constipation

• Usually a later symptom
• Lead colic occurs in 85% of cases
• Involves intestines, ureters, uterus, blood vessels
• Occurs at night; attacks last minutes but recur for days/weeks
• Constipation is usual; diarrhoea or vomiting may occur

5. Lead Palsy (Peripheral Neuropathy)

• Occurs late, seen in < 10% of cases
• Tremors, numbness, hyperesthesia, cramps precede weakness
• Wrist drop (radial nerve) - most classic presentation
• Also: deltoid, biceps, anterior tibial (foot drop)
• Rarely: eye muscles, intrinsic muscles of hand/foot
• Pathology: degeneration of nerve + atrophy of muscles
• More common in adult men

6. Encephalopathy

• Present in some form in almost every case
• More common in children, often associated with tetraethyl lead
• Symptoms: vomiting, headache, insomnia, visual disturbances, irritability, restlessness, delirium, hallucinations, convulsions, coma, death
• 85% have permanent brain damage; death in ~25%
• Usually irreversible

7. Cardiovascular & Renal

• Vascular constriction → hypertension
• Permanent arteriolar degeneration
• Chronic arteriosclerotic nephritis + interstitial nephritis

8. Reproductive

• Menstrual derangements: amenorrhoea, dysmenorrhoea, menorrhagia
• Miscarriage, premature birth

9. Other

• Low IQ in children
• Memory loss, mood disorders
• Muscle and joint pain

Inorganic vs Organic Lead - Key Difference

Diagnosis (Park's PSM)

Preventive Measures (Park's PSM)

1. Substitution - replace lead compounds with less toxic materials
2. Isolation - enclose and segregate processes generating lead dust/fumes
3. Local exhaust ventilation - promptly remove fumes and dust
4. Personal protection - approved respirators
5. Good housekeeping - wet sweeping of floors, benches; keep clean
6. Working atmosphere - lead concentration < 2.0 mg per 10 cubic metres of air (permissible limit)
7. Periodic examination - urinary lead, blood lead, RBC count, Hb, coproporphyrin test, basophilic stippling
8. Personal hygiene - hand-washing before eating; no food in work areas
9. Health education - educate workers on risks and protection

Management

• Remove from further exposure
• Saline purge - removes unabsorbed lead from gut
• Ca-EDTA (Calcium disodium versenate) - chelating agent, promotes lead excretion in urine
• d-Penicillamine - chelating agent (effective, oral)
• BAL (British Anti-Lewisite) - used in combination with Ca-EDTA
• DMSA (Dimercaptosuccinic acid) - effective combination
• Peritoneal or haemodialysis (severe cases)
• Symptomatic treatment

Quick MCQ Points

• Plumbism = Lead poisoning = Saturnism/Saturnine poisoning
• Lead: a typical cumulative poison; lead vapour more dangerous than dust
• Notifiable + compensatable in India since 1924
• Wrist drop: radial nerve affected
• Burtonian line: lead sulphide on gum margin
• Basophilic stippling: also seen in arsenic and zinc poisoning
• Tetraethyl lead: absorbed through skin → CNS effects
• Blood lead diagnostic threshold: 70 μg/100 ml

Sickness Absenteeism - Park's PSM

Definition / Importance

Absenteeism is a useful index in industry to assess the state of health of workers, and their physical, mental, and social well-being.

Incidence (India)

• India has a working force of about 30 million in registered factories
• Research by the National Productivity Council (NPC) showed:
  • Early 1950s: 8-13%
  • Recent years: 15-20% or more
• Rate of absenteeism reported: 8 to 10 days per head per year

Causes of Sickness Absenteeism

(a) Economic Causes

• If the worker is entitled to sick leave with pay, he tends to avail of this privilege by reporting sick
• Workers declare themselves fit or unfit for work at their own choice

(b) Social Causes

• Social and family obligations - weddings, festivals, repair of ancestral house
• Workers from rural areas return to villages during sowing and harvest seasons

(c) Medical Causes

• About 10% of days lost are due to occupational accidents
• Respiratory and alimentary illnesses are important causes

(d) Non-occupational Causes

• Nutritional disorders
• Alcoholism
• Drug addiction

Measurement Indices (High-Yield for Exams)

Prevention / Reduction of Sickness Absenteeism

1. Good factory management and practices
2. Adequate pre-placement examination - place workers in jobs suited to their health and capacity
3. Good human relations - between management and workers
4. Application of ergonomics - fitting the job to the worker

Additional Points for Exam

Key Takeaway (MCQ Anchor)

Sickness absenteeism is NOT always due to sickness - economic, social, and non-occupational factors all contribute. It serves as an index of the health and well-being of the workforce. Prevention rests on good management, pre-placement examination, human relations, and ergonomics.

The Factories Act, 1948 - Park's PSM

Background

• The first Indian Factories Act dates back to 1881
• Revised and amended several times
• Latest amendment: Factories (Amendment) Act, 1987
• Factory laws exist because society has an obligation to protect worker health - the worker is more important than the machine he operates

• Employees' State Insurance Act, 1948
• Mines Act
• Plantation Act
• Minimum Wages Act
• Maternity Benefit Act

1. Scope (Definition of Factory)

• No distinction between perennial and seasonal factories
• 1976 amendment: 'worker' includes contract labour employed in the manufacturing process
• Applies to the whole of India (except J&K at the time of writing)
• State Governments appoint Chief Inspector of Factories + Additional/Joint/Deputy Chief Inspectors

2. Health, Safety and Welfare (Chapters III, IV, IVA & V)

Health Provisions

• Cleanliness, lighting, ventilation
• Treatment of wastes and effluents
• Elimination of dusts and fumes
• Provision of spittoons
• Control of temperature
• Supply of cool drinking water during summer
• Employment of cleaners to keep water closets clean

Safety Provisions

• Casing of new machinery
• Devices for cutting off power
• Hoists, lifts, cranes and lifting devices
• Protection of eyes
• Precautions against dangerous fumes, explosive and inflammable substances
• Workers cannot be required to lift/carry loads likely to cause injury
• State Governments prescribe maximum weights for men, women and children
• 1976 amendment (Section 40B): Appointment of Safety Officers in every factory with 1,000 or more workers

Welfare Provisions (Chapter V)

• Washing facilities
• Facilities for storing and drying clothes
• Facilities for sitting
• First-aid appliances
• Shelters, rest-rooms and lunch rooms

3. Employment of Young Persons

• Children below 14 years: Prohibited from employment in any factory
• Persons 15-18 years = Adolescents
  • Must be certified by Certifying Surgeons regarding fitness for work
  • Allowed to work only between 6 AM and 7 PM
• Restrictions on employment of women and children in dangerous occupations

4. Hours of Work

5. Leave with Wages

6. Occupational Diseases (Notifiable)

• Factory management must report: specified accidents causing death, serious bodily injury, or occupational diseases
• 1976 amendment added to the list of notifiable diseases:
  1. Byssinosis
  2. Asbestosis
  3. Occupational dermatitis
  4. Noise-induced hearing loss
• Provision for enquiry in every case of a fatal accident
• Provision for safety and occupational health surveys in factories

7. Employment in Hazardous Processes (Chapter IV-A, 1987 Amendment)

• Site Appraisal Committee: consisting of Chief Inspector + other members (not more than 14) for examination of service conditions in factories involving hazardous processes

Quick Revision Table - Key Numbers