Workplace Hazards and Control Measures

Posted on Mar 21, 2025 in Biology

Contaminants can act on the source, the media, and the recipient. Elimination should address all three points.

Factors Affecting Hearing Damage:

  • Intensity
  • Frequency
  • Type of noise
  • Exposure Duration

Noise Levels and Effects:

  • 10-20 dB(A): Barely audible.
  • 40-50 dB(A): Comfortable sound.
  • 60-65 dB(A): Normal city noise.
  • 85 dB(A): Warning!
  • 100-200 dB(A): Noise nuisance. Difficult to talk.
  • 120-130 dB(A): Threshold of pain.
  • 140 dB(A) or more: One exposure may cause permanent hearing loss.

Levels without Personal Protective Equipment (PPE):

  • Noise Level (dB): 85, 90, 95 … 115 (+5)
  • Permitted Hours of Overexposure: 8, 4, 2 …, 1/8 (divided by 2 for every 5dB increase)

Controls in the Transmission Path:

  • Installation of insulation barriers (e.g., wood fiber, mineral wool, cork).
  • Sound insulation of walls, ceilings, and floors with cushioning and absorbent material.
  • Installation of isolated operator cabins where the process can be controlled.

Controls at the Receiver:

  • Medical supervision.
  • Use of Personal Protective Equipment (PPE).
  • Reduced hours of exposure.

Occupational Health

Occupational health is a set of disciplines that seek to promote and maintain the highest degree of physical, mental, and social well-being of workers in all occupations. It involves the prevention of health loss resulting from working conditions, protection against risk factors, and the placement and maintenance of workers in jobs suited to their physiological and psychological capabilities. It’s about the adaptation of work to the individual and each individual to their work.

Workplace Hazards:

  • Chemical Hazards: Dust, liquids, gases.
  • Physical Hazards: Noise, vibration, inadequate lighting, radiation, extreme temperatures.
  • Biological Hazards: Viruses and bacteria.
  • Mechanical Hazards/Accidents: Falls, being struck with or by objects, entrapment, falls from different levels, etc.
  • Ergonomic Hazards: Monotony, work pressures, overload, improper postures, metabolic cycles, psychosocial factors (shift work, overtime), interpersonal relationships, and emotional factors.

Routes of Entry for Toxic Substances:

Hierarchy: Respiratory and skin, digestive, parenteral.

Respiratory Route

  • Larger particles deposit and are expelled by expectoration.
  • Gases and vapors reach the alveoli, where they can cause damage and enter the bloodstream, distributing the contaminant throughout the body.
  • Absorption is a function of the contaminant’s concentration.

Skin Contact:

  • The skin is the second most important route of entry.
  • Once through the skin, substances reach the capillaries and enter the bloodstream.
  • Some poisons cause damage to the dermis (e.g., caustic soda).
  • Others penetrate and cause organ damage as they are distributed by the blood.

Ingestion (Mouth):

  • A minor route unless one drinks, eats, or smokes at the workplace.
  • Toxics can then enter by absorption in the gastrointestinal tract.

Parenteral Route:

  • Direct penetration of the toxic substance into the body through a wound or incision in the skin.
  • Usually accidental poisoning.

Variables Affecting Health (ALA):

  • Chemical concentration.
  • Route of entry.
  • Exposure time.
  • Individual susceptibility.
  • Frequency of exposure.
  • Previous work experience.
  • Drug interactions.
  • Controls in use.

Dust:

A suspension in the air of small solid particles, from physical disintegration processes.

Classification of Dust:

By size, shape, composition, and effect.

By Size:

  • Sediment: Due to their weight, they settle quickly. Their size ranges from 10 to 150 microns.
  • Inhalable: Can penetrate the respiratory system, with a size smaller than 10 microns.
  • Respirable: Can penetrate the lungs, with a size smaller than 5 microns.
  • Visible: Distinguishable to the naked eye, their size is greater than 40 microns.

Particle Behavior in the Body:

  • Particles around 10 microns enter the respiratory system and are retained by the mucosa of the nose, throat, trachea, and bronchi. They are removed by the body’s cleaning mechanisms.
  • Particles around 5 microns: Enter the alveolar spaces.