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12/19/22 ACCIDENT CAUSATION Why Do We Have Accidents? Lecture 7 IE438. Industrial Safety and Health Dr. Majed Moosa 1 CAUSATION HISTORY • Early man – Accidents were the result of Bad Spirits • Civilized man - Injured person was at fault due to stupidity 2 1 12/19/22 CAUSATION HISTORY • In...

12/19/22 ACCIDENT CAUSATION Why Do We Have Accidents? Lecture 7 IE438. Industrial Safety and Health Dr. Majed Moosa 1 CAUSATION HISTORY • Early man – Accidents were the result of Bad Spirits • Civilized man - Injured person was at fault due to stupidity 2 1 12/19/22 CAUSATION HISTORY • Industrial revolution – carelessness caused accidents. • Natural side effect of production • Cost of doing business • Human nature – people will always be careless 3 CAUSATION HISTORY • The court system • Upheld the view of individual responsibility • Injured worker had to sue • Employer had to be found completely to blame • Public opinion • Rose against the "worker alone-is-to-blame" theory. • Courts became more responsive to workers' claims. • By 1908 State legislatures implemented an employer's liability law. 4 2 12/19/22 CAUSATION HISTORY • Employers take notice • Financial responsibility for an injured worker • More cost effective to prevent accidents. • Only theory remained personal carelessness • Safety program success was hit and miss 5 INDUSTRIAL REVOLUTION Natural Side Effect of Production “Acts of God” ACCIDENTS Number Is Up Approach People Errors Carelessness Employers Rationale for Accidents 6 3 12/19/22 THEORIES OF ACCIDENT CAUSATION There are several major theories concerning accident causation, each of which has some explanatory and predictive value. 1.The domino theory developed by H. W. Heinrich, a safety engineer and pioneer in the field of industrial accident safety. 2.Human Factors Theory 3.Accident/Incident Theory 4.Epidemiological Theory 5.Systems Theory 6.The energy release theory, developed by Dr. William Haddon, Jr., of the Insurance Institute for Highway Safety. 7.Behavior Theory Accident theories guide safety investigations. They describe the scope of an investigation. 7 HEINRICH’S THEORY • Scientific Approach Heinrich’s model to accident causation has been the basic approach in accident prevention and has been used mostly by safety societies and professional people since its publication in 1932. This was the first scientific approach. 8 4 12/19/22 HEINRICH’S ACCIDENT CAUSATION MODEL • The factors can be visualized as a series of dominoes standing on edge; when one falls, the linkage required for a chain reaction is completed. • Each of the factors is dependent on the preceding factor. Social Environment & Ancestry Unsafe Act Or Unsafe Condition Fault of the Person Mistakes of People Accident Injury According to Heinrich, an "accident" is one factor in a sequence that may lead to an injury. 9 ACCIDENT CAUSATION 1932 - First Scientific Approach To Accident Prevention – Heinrich's Domino Theory “Industrial Accident Prevention” Social Environment and Inherited Behavior (e.g., alcoholism) Fault of the person (carelessness, bad temper, recklessness, etc) Unsafe act or condition – Performing a task without the appropriate PPE Accident Injury – outcome of some accidents but not all MISTAKES OF PEOPLE 10 5 12/19/22 HEINRICH’S DOMINOS – THE PROCESS 1. A personal injury (the final domino) occurs only as a result of an accident. 2. An accident occurs only as a result of a personal or mechanical hazard. 3. Personal and mechanical hazards exist only through the fault of careless persons or poorly designed or improperly maintained equipment. 4. Faults of persons are inherited or acquired as a result of their social environment or acquired by ancestry. 5. The environment is where and how a person was raised and educated. 11 THREE “E’S” OF ACCIDENT PREVENTION • Engineering – Control hazards through product design or process change • Education – Train workers regarding all facets of safety – Impose on management that attention to safety pays off • Enforcement – Insure that internal and external rules, regulations, and standard operating procedures are followed by workers as well as management. 12 6 12/19/22 BEYOND ENGINEERING • Instruction • Persuasion • Discipline 13 MODERN CAUSATION MODEL • Parallels Heinrich’s theory • “Injury” becomes “Result” • Varies from no damage to very severe • “Accident” becomes “Mishap” • Injury not required • “Unsafe Act or Unsafe Condition” becomes “Operating Error” • Act and condition captured as error 14 7 12/19/22 MODERN CAUSATION MODEL No damage or injury OPERATING ERROR RESULTS MISHAP Major damage Or fatalities 15 MODERN CAUSATION MODEL Disrupted Operation No damage or injury OPERATING ERROR RESULTS MISHAP RESULTS Major damage Or fatalities 16 8 12/19/22 MODERN CAUSATION MODEL Event Disrupted Operation No damage or injury OPERATING ERROR RESULTS MISHAP RESULTS Major damage Or fatalities 17 MODERN CAUSATION MODEL Failure to properly operate or maintain facilities or equipment Event Injury or damage No damage or injury OPERATING ERROR RESULTS MISHAP RESULTS Major damage Or fatalities 18 9 12/19/22 MODERN CAUSATION MODEL Single Most Important Addition to New Model SYSTEM DEFECT System Defect No damage or injury OPERATING ERROR MISHAP “Accident” RESULTS RESULTS Major damage Or fatalities 19 SYSTEM DEFECTS • Weaknesses in the way the system is designed or operated • Improper assignment of responsibilities • Improper climate of motivation • Inadequate training and education • Inadequate or improper equipment or supplies • Poor personnel selection for job • Inadequate funding 20 10 12/19/22 MODERN CAUSATION MODEL COMMAND/ MANAGEMENT ERROR SYSTEM DEFECT No damage or injury OPERATING ERROR MISHAP RESULTS RESULTS Major damage Or fatalities 21 MANAGEMENT ERROR • Managers • Design systems • Create procedures • Enforce discipline • Provide training Why does the manager fail to identify system defects or take action? 22 11 12/19/22 MODERN CAUSATION MODEL SAFETY PROGRAM DEFECT COMMAND/ MANAGEMENT ERROR SYSTEM DEFECT No damage or injury OPERATING ERROR MISHAP RESULTS RESULTS Major damage Or fatalities 23 SAFETY PROGRAM DEFECT • Ineffective information collection • Weak causation analysis • Poor countermeasures • Inadequate controls • Inadequate programs 24 12 12/19/22 MODERN CAUSATION MODEL SAFETY MANAGEMENT ERROR SAFETY PROGRAM DEFECT COMMAND/ MANAGEMENT ERROR SYSTEM DEFECT No damage or injury OPERATING ERROR MISHAP RESULTS RESULTS Major damage Or fatalities 25 SAFETY MANAGEMENT ERROR • Knowledge • Motivation • Integration • Relevance 26 13 12/19/22 SEVEN AVENUES There are seven avenues through which we can initiate countermeasures. None of these areas overlap. They are: § Safety management error § Safety program defect § Management / Command error § System defect § Operating error § Mishap § Result 27 MODERN CAUSATION MODEL 1 2 3 SAFETY MANAGEMENT ERROR SAFETY PROGRAM DEFECT 4 COMMAND/ MANAGEMENT ERROR SYSTEM DEFECT 5 6 No damage or injury OPERATING ERROR MISHAP RESULTS RESULTS 7 Major damage Or fatalities 28 14 12/19/22 HUMAN FACTORS THEORY Heinrich posed his model in terms of a single domino leading to an accident. The premise here is that human errors cause accidents. These errors are categorized broadly as: • OVERLOAD - The work task is beyond the capability of the worker 1.Includes physical and psychological factors 2.Influenced by environmental factors, internal factors, and situational factors • INAPPROPRIATE WORKER RESPONSE - To hazards and safety measures (worker’s fault) - To incompatible work station (management, environment faults) • INAPPROPRIATE ACTIVITIES - Lack of training and misjudgment of risk But the structure of this theory is still a cause/effect format. 29 HUMAN FACTORS THEORY 30 15 12/19/22 END 31 16