2. 1 Instructor: Lee Reynolds, Associate Professor Department of Engineering Technology Texas Tech University

3. 2 Definitions and Theories Sources: Harvey F. Thomas, Ph.D., CSP, CHMM Industrial Safety and Health, David Goetsch, Merrill Publishers, pgs. 29- 39

4. 3 Learning Objectives Know the definitions attendant to safety and health management Know the basic theories of accident causation

5. 4 What is Safety “Is it safe to go into the trench? “I’m worried about her safety harness” “He’s not a very safe driver” “Does that nail gun have a safety latch?”

6. 5 What is safety & health discipline? Multi-faceted An ill-defined domain Multi-discipline http://www.life.uiuc.edu/crofts/bc-complex_site/chick-bc-complex.gif http://www.colored-diamonds.com/page7.htm

7. 6 Safety & Health Discipline Interactions Environmental OperationsMedical Industrial Hygiene Safety & Health Transportation Information Systems Facilities Test and evaluation Legal Training

8. 7 What does safety mean? Definition of Terms “Safety is the prevention of accidents and the mitigation of personal injury or property damage which may result from accidents.” Mroz This presentation is an introduction to concepts presented in text article, Landmarks in the History of Safety, pp.10-15.

9. 8 What does the term “accident” mean? “.. An accident is a potentially harmful energy flow or environmental condition that is preceded by planning or operation oversight or omissions, resulting in conditions or actions that trigger the incident…..”

10. 9 Then what is safety relative to an accident? “Safety is a condition or state of being resulting from the modification of human behavior, and/or design of the physical environment to reduce the possibility of hazards, thereby reducing accidents.” Strasser et al.

11. 10 Incident vs. Accident Accidental triad 1. When an unwanted energy flow occurs or a hostile environmental condition develops. 2. Barriers or controls << than adequate. 3. Persons or objects are in the energy path or exposed to the environmental condition… The accidental triad is complete.

12. 11 Definition of terms Approaches to Use of Barriers. 1.Barriers on the energy source. 2.Barriers on the targets (person or objects). 3.Barriers between the energy flow and the targets. 4.Separation of the flow and targets by time or space.

13. 12 Definition of Terms Incident – an incident is not an accident--there have been no losses. The worst that has happened is a near miss. No persons or objects were in the energy flow. You can remove the person from the energy flow or place a barrier between him and the energy flow.

14. 13 Definition of Terms We all need energy to do our jobs and live our lives. Then Safety can be defined as the preplanned management of energy without damaging or harmful energy flows. You manage energy flow through people and materiel resources.

15. 14 “.. the absence of adequate barriers or controls, causes losses-injury, damage, or degraded performance-to the persons or objects in the path of the energy flow or exposed to the environmental conditions..”

16. 15 “That occurrence in a sequence of events which usually produces unintended injury, death, or property damage”. National Safety Council

17. 16 Definition of Terms Hazard – condition or set of conditions that have the potential to produce injury and/or property damage. Risk- probability that a hazard will be activated and produce injury or property damage and the severity of the hazard.

18. 17 Definition of Terms Risk involves two components – –(1) likelihood that negative situation will occur. –(2) severity of injury or damage if the hazard is activated.

19. 18 Components of risk –probability and severity http:// www.murtongroup.com/images/riskmatrix.gif Risk Highest Risk

20. 19 Definition of Terms continued… Loss control – accident prevention achieved through complete safety and health hazard control program. Hazard control – developing program to recognize, evaluate, and eliminate destructive effects of hazards. Hazards can be either human errors or workplace conditions.

21. 20 Definition of Terms continued… Accident prevention-elimination of factors and conditions that pose hazard and risk. Accident mitigation-direct confrontation of accident causative factors.

22. 21 Definition of Terms Injury – damage or harm to body as result of violence, infection or other source. Illness – environmental stress resulting in abnormal physiological condition. Acute illness – immediate effects Chronic illness – long term effects.

23. 22 Why do accidents happen?

24. 23 Theories of Accident Causation Major theories presented include:  Domino Theory of accident causation.  Human Factors Theory of Accident Causation

25. 24 Accident/Incident Theory of Accident Causation. Epidemiological Theory of Accident Causation. Combination Theory of Accident Causation.

26. 25 Why do Employees get Hurt on the JOB? Accident Prone? Carelessness?

27. 26 Equipment Failure? Hazardous Work?

28. 27 Theories of Accident Causation Single Factor Theory H. W. Heinrich’s Domino Theory (1932) Study concluded that: 88% industrial accidents caused by fellow workers’ unsafe acts.

29. 28 10% by unsafe conditions. 2% unavoidable.

30. 29 Theories of Accident Causation Heinrick’s Axioms of Industrial Safety Injuries result from completed series of Factors, including injury itself.

31. 30 Theories of Accident Causation Heinrich’s Axioms Accident can occur through unsafe act or mechanical hazard. Most accidents due to unsafe behavior by people.

32. 31 Unsafe act by person or condition not always accident ending. i.e. near misses.

33. 32 Theories of Accident Causation Select corrective actions by identifying cause. Severity accidental and accident preventable. Best quality = best accident prevention technique.

34. 33 Theories of Accident Causation Management assume responsibility for safety. Supervisor key in preventing industrial accidents. Both direct and indirect costs with accidents.

35. 34 Heinrich’s Domino Theory Three Phases Pre-Contact Phase Contact Phase Post-Contact Phase

36. 35 Heinrich’s Domino Theory Theory has two central points: Injuries caused by action of preceding factors. Removal of central factor (unsafe act/hazardous) negates the action of preceding factors. Prevents accidents via elimination.

37. 36 Heinrich’s Domino Theory Five Factors Influence ALL Accidents 1) Ancestry & Social Environment 2) Fault of The Person 3) Unsafe Act/ Mechanical or Physical Hazard 4) Accident 5) Injury

38. 37 Human Factors Theory of Accidents Chain of events caused by human error. Three factors lead to human error: Overload. Inappropriate response. Inappropriate activities.

39. 38 Overload Inappropriate activities Inappropriate response Human errors factor Factors that cause human errors

40. 39 Overload Inappropriate response Inappropriate activities Environmental factors Internal factors Situational factors Detecting a hazard but not correcting it. Removing safeguards Ignoring safety Performing tasks without the requisite training Misjudging risks Human Factors Theory

41. 40 Accident/Incident Theory Overload Ergonomic Traps Decision to Err Human Error System Failure

42. 41 Petersen’s Accident/Incident Theory Systems failure OverloadErgonomic Traps Pressure Fatigue Motivation Drugs, alcohol Worry Incompatible workstation Incompatible expectations Decision to err. Misjudgment of the risks Unconscious desire to err Logical decision Responsibility Training Policy Inspection Human Error Accident Injury/damage

43. 42 Perceptions Environmental Factors Susceptibility of people Predisposition Characteristics Situational Characteristics Risk assessment by individuals Peer pressure Priorities of the supervisor Attitude Epidemiological Theory Can cause or prevent accident conditions

44. 43 Systems Theory Person Machine Environment Collect Information Weigh Risks Make Decisions Task to be Performed

45. 44 System Theory of Causation Persons Task to be performed Persons Machine Interaction Environment Collect information Weigh risks Make decision Feedback Loop Stress factors???

46. 45 System Theory of Causation Firenzie recommendation factors before beginning collecting, weighing,and making decisions. Job requirements. Worker’s abilities and limitations.

47. 46 Loss if task is attempted but fails. Loss if task is not attempted.

48. 47 Energy-Related Accident Causation Theory Accidents can be prevented by controlling the energy involved or changing the structures that cause the damage.

49. 48 Energy-Related Accident Causation Theory Limit the Energy Substitute a Safer Form of Energy Prevent Energy Build-up

50. 49 Prevent the Release of the Energy Provide for a Slow Release of the Energy Channel the Release Away

51. 50 Energy-Related Accident Causation Theory Place a Barrier on the Energy Source. Place a Barrier Between the Energy and Person. Place a Barrier on the Person.

52. 51 Raise the Injury or Damage Threshold. Ameliorate the Effects. Rehabilitate.

53. 52 Combination Theory Often cause of accident cannot be explained by one theory. Cause may be due to parts of several different models to varying degrees.

54. 53 Behavioral Scientists McGregor Herzberg Likert Argyris Blake and Mouton Skinner

55. 54 Theories of Accident Causation Summary The domino theory of accident causation was one of the earliest developed. The human factor theory of accident causation attributes accidents to a chain of event caused by human error.

56. 55 Theories of Accident Causation

57. 56 Theories of Accident Causation Epidemiological theory-models for epidemiological factors and disease good for epidemiological factors and accident. Systems theory views accident situation as combination of person, machine and environment.

58. 57 Combination theory claims that no one model/theory can explain all accident.

59. 58 Questions????