Theories of Accident Causation and Prevention in the Workplace

Posted on Sep 11, 2024 in Other subjects

Theories of Accident Causation

Accident causation refers to the factors that are the primary reasons behind an accident. For occupational health and safety professionals, determining causation factors in any workplace injury or accident is key. Understanding what caused an unsafe situation to occur is important in implementing measures to help prevent a reoccurrence.

There are several major theories concerning accident causation:

  • The Domino Theory (developed by H.W. Heinrich)
  • Human Factors Theory
  • Accident/Incident Theory
  • Epidemiological Theory
  • Systems Theory
  • The Energy Release Theory (developed by Dr. William Haddon)
  • Behavior Theory

Domino Theory

The Domino Theory of accident causation stipulates that injuries occur because of a series of factors, one of which is an accident. In the Domino Theory, all factors are connected, and each of them is dependent on the preceding factor. This means that personal injury (represented as the final domino) occurs only as a result of an accident, and the accident itself occurs only as a result of a personal or mechanical hazard.

Human Factors Theory

A chain of events that is or was caused by consistent human error leads to an accident.

  • Overload: When an individual is overwhelmed by environmental, internal, or situational factors.
  • Inappropriate Response: Failure to react properly to known hazards or ignoring safety measures.
  • Inappropriate Activities: Engaging in tasks without proper training or misjudging the level of risk involved.

Safety Committee in an Organization

Composition

  • Includes members from various departments: management, frontline workers, office staff, safety specialists, and medical officers.
  • Equal representation of management and employees to ensure balanced input.
  • Broadly represents the workforce for effective safety management.
  • Regular meetings, at least once a month.

Role and Function

  • Provides a formal mechanism for consultation on safety matters between employees and management.
  • Facilitates direct communication, allowing employees to share practical experiences and knowledge.
  • Strengthens mutual trust and confidence through actions taken by management to improve safety.
  • Identifies best practices and provides opportunities for input, questions, and concerns.

Major Functions

  • Accident Prevention: Identifies probable causes of accidents and unsafe practices; suggests remedial measures to prevent accidents.
  • Safety Promotion: Organizes activities such as safety weeks, competitions, talks, and film shows to raise awareness.
  • Work Area Inspection: Conducts rounds of the workplace to check for unsafe practices and conditions; recommends remedial measures for rectification, including first-aid and medical facilities.
  • Health Hazard Assessment: Evaluates health hazards related to handling explosives, chemicals, and other materials; suggests remedial measures, including the use of PPE.
  • Welfare and Amenities: Recommends improvements in welfare amenities and other aspects of safety, health, and welfare.

Work Permit System: Key Points

  • A work permit system is a formal written system to control hazardous work.
  • A work permit is a document specifying the work to be done and safety precautions to be taken.
  • Ensures that work starts only after safe procedures have been defined and hazards considered.
  • An important element of Safety Management to ensure a safe working environment.
  • Reduces the possibility of injury, protects property, and prevents fire, explosion, and environmental damage.
  • Permits should be printed, serially numbered, and may have color codes for different types.
  • Permit issuing authority must ensure all conditions are met before issuing the permit.
  • Permits should be returned to the originating department after job completion, and records maintained for a month.
  • Examples of high-risk activities:
    • Entry into confined spaces
    • Work near overhead power lines and telecommunication cables
    • Hot work

Objectives of the Work Permit System

  • Control over maintenance activities by assigning responsibilities.
  • Ensuring communication.
  • Proper consideration of job hazards and precautions.
  • Ensures work is properly defined and authorized.
  • Operating personnel are aware of ongoing work and necessary precautions.
  • Workers executing the job understand the hazards involved.

Hot Work Permit

  • Hot work involves tasks where temperatures are high enough to cause burning (e.g., welding, cutting, heating).
  • Hot work must not be carried out without a hot work permit issued by a responsible officer.
  • Hot work permits are red-colored, used for tasks that generate heat or sparks.
  • Three hazardous situations to consider:
    • Presence of flammable materials in the equipment
    • Presence of combustible materials that burn or emit flammable vapors when heated
    • Presence of flammable gas in the atmosphere or adjacent areas

Cold Work Permit

  • Cold work permits are green-colored, used for hazardous maintenance work that does not involve hot work.
  • Used when no flammable or explosive risks are identified.
  • Examples of cold work:
    • Blanking or deblanking
    • Connecting and disconnecting pipe work
    • Removing and fitting valves
    • Work on pumps
    • Cleaning or removing oily residues

5S of Housekeeping

  1. Sort – Eliminate unnecessary items, archive what you may need, and decide what is needed on a daily or weekly basis.
  2. Set in Order – Arrange items for easy access, label, mark locations, and use color codes to make everything clear.
  3. Shine & Clean – Clean and check items for good working order; repair broken items and ensure a thorough cleaning is done.
  4. Standardization – Set new cleanliness standards, take photos, share ideas, and ensure consistency across the factory.
  5. Sustain – Maintain the cleanliness and organization with regular audits, ensuring everyone knows where items belong and tracking improvements.

Types of PPE

1. Respiratory Protective Equipment:

  • Air Line Respirator: Provides air through a hose; limited by hose length; ensures air supply is clean.
  • Suction Hose Mask: Full face-piece with a flexible hose; air is drawn by breathing effort; hose has a filter.
  • Pressure Hose Mask: Similar to suction hose mask but uses a blower to force air through the hose.
  • Self-Contained Breathing Apparatus:
    • Compressed Air/Oxygen: Uses cylinders for air or oxygen supply.
    • Oxygen-Regenerating: Absorbs moisture and CO2 from exhaled breath; regenerates oxygen.
  • Chemical Filters:
    • Canister Gas Masks: Full face-piece with a canister that absorbs contaminants.
    • Chemical Cartridge Respirator: Half mask with cartridges for gases or vapors.
    • Self-Rescue Respirators: Compact device for emergency escape with a filter, mouthpiece, and nose clip.
  • Mechanical Filters: Remove particulate matter; single-use or reusable; may include micro filters for fine dust.
  • Combination Filters: Combine chemical and mechanical filters for toxic gases and particulate matter.

2. Non-Respiratory Protective Equipment:

  • Head Protection: Hard hats and protective caps for protection against falling objects, sparks, and heat.
  • Eye and Face Protection: Safety spectacles, goggles, welding helmets, face shields, and hoods for protection from dust, particles, splashes, and radiation.
  • Hand and Arm Protection: Gloves, mittens, hand guards, and arm sleeves for handling sharp objects, hot materials, and chemicals.
  • Body Protection: Aprons, overalls, jackets, and full suits for protection from various hazards.
  • Foot and Leg Protection: Safety shoes, boots, leggings, and guards for protection against heavy materials, corrosive substances, and molten metals.
  • Ear Protection: Devices to protect against high noise levels that can affect well-being and safety.

Excavation

Excavation work poses several risks, including cave-ins, falling materials, hazardous atmospheres, and underground utilities.

Risks:

  1. Cave-ins: Unstable soil can collapse, burying workers and causing fatalities.
  2. Falling Loads: Materials or equipment falling into the excavation site pose a significant risk.
  3. Hazardous Atmospheres: Poor ventilation in excavated spaces can lead to the accumulation of toxic gases or a lack of oxygen.

Precautions:

  • Shoring and Trenching: Properly designed support systems should be used to prevent cave-ins.
  • Sloping: Excavations should be sloped appropriately to prevent collapses.
  • Regular Inspections: Excavation sites should be inspected daily, and more frequently if conditions change, to ensure safety.

Entry into Confined Spaces

Definition:

A confined space is an area with limited openings for entry and exit, unfavorable ventilation, and potential dangerous air contaminants, not intended for continuous occupancy. Examples include tanks, ship compartments, process vessels, pits, wells, sewers, boilers, ventilation ducts, and pipelines.

Characteristics of Confined Spaces:

  • Large enough for an individual to enter.
  • Limited or restricted means for entry or exit.
  • Not intended for continuous human occupancy.
  • Unfavorable natural ventilation.

Common Hazards:

  • Oxygen deficiency.
  • Flammable atmosphere.
  • Toxic gases.

Safe Work Procedure Components:

  1. Pre-entry Planning:
    • Conduct and verify a hazard assessment before entry.
    • Obtain a valid entry permit.
    • Secure the site with signs, barricades, and traffic control devices.
    • Ensure all necessary equipment is available and operational.
    • Perform a pre-entry atmospheric assessment; use respiratory protection if necessary.
    • Identify and control atmospheric hazards; ventilate the space if possible.
    • Check for physical hazards.
    • Obtain a hot work permit if applicable.
    • Ensure all workers are familiar with emergency procedures.
    • For hazardous atmospheres, ensure workers:
      • Use appropriate respiratory protection.
      • Are in communication with someone stationed at the entrance.
      • Understand and have access to rescue procedures and equipment.
      • Are familiar with the employer’s confined space entry code of practice.
      • Are capable of performing a rescue if needed.
  2. Entry Procedures:
    • Follow procedures for entry, working within, and exiting the confined space.
  3. Rescue Procedures:
    • Develop an emergency response plan that includes:
      • Identification of potential emergencies.
      • Procedures for managing emergencies.
      • Location and use of emergency equipment.
      • Training requirements for responders.
      • Emergency facilities and fire protection requirements.
      • Alarm and communication protocols.
      • First-aid services.
      • Rescue and evacuation procedures and designated personnel.
      • Emergency transportation.