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Theory of Accident Causes

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Accidents are defined as unplanned occurrences which result in injuries, fatalities, loss of production or damage to property and assets. Preventing accidents is extremely difficult in the absence of an understanding of the causes of accidents. Many attempts have been made to develop a prediction theory of accident causation, but so far none has been universally accepted. Researchers from different fields of science and engineering have been trying to develop a theory of accident causation which will help to identify, isolate and ultimately remove the factors that contribute to or cause accidents. In this article, a brief outline of various accident causation theories is presented, followed by a structure of accidents.

Accident Causation Theories

The domino theory

According to W.H. Heinrich (1931), who developed the so-called domino theory, 88% of all accidents are caused by unsafe acts of people, 10% by unsafe actions and 2% by “acts of God”. He proposed a “five-factor accident sequence” in which each factor would actuate the next step in the manner of toppling dominoes lined up in a row. The sequence of accident factors is as follows:

  1. ancestry and social environment
  2. worker fault
  3. unsafe act together with mechanical and physical hazard
  4. accident
  5. damage or injury.


In the same way that the removal of a single domino in the row would interrupt the sequence of toppling, Heinrich suggested that removal of one of the factors would prevent the accident and resultant injury; with the key domino to be removed from the sequence being number 3. Although Heinrich provided no data for his theory, it nonetheless represents a useful point to start discussion and a foundation for future research.

Multiple causation theory

Multiple causation theory is an outgrowth of the domino theory, but it postulates that for a single accident there may be many contributory factors, causes and sub-causes, and that certain combinations of these give rise to accidents. According to this theory, the contributory factors can be grouped into the following two categories:

Behavioural. This category includes factors pertaining to the worker, such as improper attitude, lack of knowledge, lack of skills and inadequate physical and mental condition.

Environmental. This category includes improper guarding of other hazardous work elements and degradation of equipment through use and unsafe procedures.

The major contribution of this theory is to bring out the fact that rarely, if ever, is an accident the result of a single cause or act.

The pure chance theory

According to the pure chance theory, every one of any given set of workers has an equal chance of being involved in an accident. It further implies that there is no single discernible pattern of events that leads to an accident. In this theory, all accidents are treated as corresponding to Heinrich’s acts of God, and it is held that there exist no interventions to prevent them.

Biased liability theory

Biased liability theory is based on the view that once a worker is involved in an accident, the chances of the same worker becoming involved in future accidents are either increased or decreased as compared to the rest of workers. This theory contributes very little, if anything at all, towards developing preventive actions for avoiding accidents.

Accident proneness theory

Accident proneness theory maintains that within a given set of workers, there exists a subset of workers who are more liable to be involved in accidents. Researchers have not been able to prove this theory conclusively because most of the research work has been poorly conducted and most of the findings are contradictory and inconclusive. This theory is not generally accepted. It is felt that if indeed this theory is supported by any empirical evidence at all, it probably accounts for only a very low proportion of accidents without any statistical significance.

The energy transfer theory

Those who accept the energy transfer theory put forward the claim that a worker incurs injury or equipment suffers damage through a change of energy, and that for every change of energy there is a source, a path and a receiver. This theory is useful for determining injury causation and evaluating energy hazards and control methodology. Strategies can be developed which are either preventive, limiting or ameliorating with respect to the energy transfer.

Control of energy transfer at the source can be achieved by the following means:

  • elimination of the source
  • changes made to the design or specification of elements of the work station
  • preventive maintenance.


The path of energy transfer can be modified by:

  • enclosure of the path
  • installation of barriers
  • installation of absorbers
  • positioning of isolators.


The receiver of energy transfer can be assisted by adopting the following measures:

  • limitation of exposure
  • use of personal protective equipment.


The “symptoms versus causes” theory

The “symptoms versus causes” theory is not so much a theory as an admonition to be heeded if accident causation is to be understood. Usually, when investigating accidents, we tend to fasten upon the obvious causes of the accident to the neglect of the root causes. Unsafe acts and unsafe conditions are the symptoms—the proximate causes—and not the root causes of the accident.

Structure of Accidents

The belief that accidents are caused and can be prevented makes it imperative for us to study those factors which are likely to favour the occurrence of accidents. By studying such factors, the root causes of accidents can be isolated and necessary steps can be taken to prevent the recurrence of the accidents. These root causes of accidents can be grouped as “immediate” and “contributing”. The immediate causes are unsafe acts of the worker and unsafe working conditions. The contributing causes could be management-related factors, the environment and the physical and mental condition of the worker. A combination of causes must converge in order to result in an accident.

Figure 1 shows the structure of accidents, including the details of immediate causes, contributing causes, types of accidents and results of accidents. This accounting is not exhaustive by any means. However, an understanding of the “cause and effect” relation of the accident-causing factors is required before continuous improvement of safety processes can be undertaken.

Figure 1. Structure of Accidents



Accident causation is very complex and must be understood adequately in order to improve accident prevention. Since safety lacks a theoretical base, it cannot be regarded as being a science yet. This fact should not discourage us, as most of the scientific disciplines—mathematics, statistics and so on—passed through a similarly tentative phase at one time or the other. Accident causation study holds great promise for those who are interested in developing the pertinent theory. At present, theories of accident causation are conceptual in nature and, as such, are of limited use in preventing and controlling accidents. With such a diversity of theories, it will not be difficult to understand that there does not exist one single theory that is considered right or correct and is universally accepted. These theories are nonetheless necessary, but not sufficient, for developing a frame of reference for understanding accident occurrences.



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Part I. The Body
Part II. Health Care
Part III. Management & Policy
Part IV. Tools and Approaches
Part V. Psychosocial and Organizational Factors
Part VI. General Hazards
Part VII. The Environment
Part VIII. Accidents and Safety Management
Accident Prevention
Audits, Inspections and Investigations
Safety Applications
Safety Policy and Leadership
Safety Programs
Part IX. Chemicals
Part X. Industries Based on Biological Resources
Part XI. Industries Based on Natural Resources
Part XII. Chemical Industries
Part XIII. Manufacturing Industries
Part XIV. Textile and Apparel Industries
Part XV. Transport Industries
Part XVI. Construction
Part XVII. Services and Trade
Part XVIII. Guides

Accident Prevention Additional Resources

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Accident Prevention References

Adams, JGU. 1985. Risk and Freedom; The Record of Read Safety Regulation. London: Transport Publishing Projects.

American National Standards Institute (ANSI). 1962. Method of Recording and Measuring Work Injury Experience. ANSI Z-16.2. New York: ANSI.

—. 1978. American National Standard Manual on Uniform Traffic Control Devices for Streets and Highways. ANSI D6.1. New York: ANSI.

—. 1988. Hazardous Industrial Chemicals—Precautionary Labeling. ANSI Z129.1. New York: ANSI.

—. 1993. Safety Color Code. ANSI Z535.1. New York: ANSI.

—. 1993. Environmental and Facility Safety Signs. ANSI Z535.2. New York: ANSI.

—. 1993. Criteria for Safety Symbols. ANSI Z535.3. New York: ANSI.

—. 1993. Product Safety Signs and Labels. ANSI Z535.4. New York: ANSI.

—. 1993. Accident Prevention Tags. ANSI Z535.5. New York: ANSI.

Andersson, R. 1991. The role of accidentology in occupational accident research. Arbete och halsa. 1991. Solna, Sweden. Thesis.

Andersson, R and E Lagerlöf. 1983. Accident data in the new Swedish information system on occupational injuries. Ergonomics 26.

Arnold, HJ. 1989. Sanctions and rewards: Organizational perspectives. In Sanctions and Rewards in the Legal System:
A Multidisciplinary Approach. Toronto: University of Toronto Press.

Baker, SP, B O’Neil, MJ Ginsburg, and G Li. 1992. Injury Fact Book. New York: Oxford University Press.

Benner, L. 1975. Accident investigations—multilinear sequencing methods. J Saf Res 7.

Centers for Disease Control and Prevention (CDC). 1988. Guidelines for evaluating surveillance systems. Morb Mortal Weekly Rep 37(S-5):1–18.

Davies, JC and DP Manning. 1994a. MAIM: the concept and construction of intelligent software. Saf Sci 17:207–218.

—. 1994b. Data collected by MAIM intelligent software: The first fifty accidents. Saf Sci 17:219-226.

Department of Trade and Industry. 1987. Leisure Accident Surveillance System (LASS): Home and Leisure Accident Research 1986 Data. 11th Annual Report of the Home Accident Surveillance System. London: Department of Trade and Industry.

Ferry, TS. 1988. Modern Accident Investigation and Analysis. New York: Wiley.

Feyer, A-M and AM Williamson. 1991. An accident classification system for use in preventive strategies. Scand J Work Environ Health 17:302–311.

FMC. 1985. Product Safety Sign and Label System. Santa Clara, California: FMC Corporation.

Gielen, AC. 1992. Health education and injury control: Integrating approaches. Health Educ Q 19(2):203–218.

Goldenhar, LM and PA Schulte. 1994. Intervention research in occupational health and safety. J Occup Med 36(7):763–775.

Green, LW and MW Kreuter. 1991. Health Promotion Planning: An Educational and Environmental Approach. Mountainview, CA: Mayfield Publishing Company.

Guastello, SJ. 1991. The Comparative Effectiveness of Occupational Accident Reduction Programs. Paper presented at the International Symposium Alcohol Related Accidents and Injuries. Yverdon-les-Bains, Switzerland, Dec. 2-5.

Haddon, WJ. 1972. A logical framework for categorizing highway safety phenomena and activity. J Trauma 12:193–207.

—. 1973. Energy damage and the 10 countermeasure strategies. J Trauma 13:321–331.

—. 1980. The basic strategies for reducing damage from hazards of all kinds. Hazard Prevention September/October:8–12.

Hale, AR and AI Glendon. 1987. Individual Behaviour in the Face of Danger. Amsterdam: Elsevier.

Hale, AR and M Hale. 1972. Review of the Industrial Accident Research Literature. Research paper No. l, Committee on Safety & Health. London: HMSO.

Hale, AR, B Heming, J Carthey and B Kirwan. 1994. Extension of the Model of Behaviour in the Control of Danger. Vol. 3: Extended Model Description. Sheffield: Health and Safety Executive project HF/GNSR/28.

Hare, VC. 1967. System Analysis: A Diagnostic Approach. New York: Harcourt Brace World.

Harms-Ringdahl, L. 1993. Safety Analysis. Principles and Practice in Occupational Safety. Vol. 289. Amsterdam: Elsevier.

Heinrich, HW. 1931. Industrial Accident Prevention. New York: McGraw-Hill.

—. 1959. Industrial Accident Prevention: A Scientific Approach. New York: McGraw-Hill Book Company.

Hugentobler, MK, BA Israel, and SJ Schurman. 1992. An action research approach to workplace health: Intergrating methods. Health Educ Q 19(1):55–76.

International Organization for Standardization (ISO). 1967. Symbols, Dimensions, and Layout for Safety Signs. ISO R557. Geneva: ISO.

—. 1984. Safety Signs and Colors. ISO 3864. Geneva: ISO.

—. 1991. Industrial Automation Systems—Safety of Integrated Manufacturing Systems—Basic Requirements (CD 11161). TC 184/WG 4. Geneva: ISO.

—. 1994. Quality Management and Quality Assurance Vocabulary. ISO/DIS 8402. Paris: Association française de normalisation.

Janssen, W. 1994. Seat-belt wearing and driving behavior: An instrumented-vehicle study. Accident analysis and prevention. Accident Anal. Prev. 26: 249-261.

Jenkins, EL, SM Kisner, D Fosbroke, LA Layne, MA Stout, DN Castillo, PM Cutlip, and R Cianfrocco. 1993. Fatal Injuries to Workers in the United States, 1980–1989: A Decade of Surveillance. Cincinnati, OH: NIOSH.

Johnston, JJ, GTH Cattledge, and JW Collins. 1994. The efficacy of training for occupational injury control. Occup Med: State Art Rev 9(2):147–158.

Kallberg, VP. 1992. The Effects of Reflector Posts on Driving Behaviour and Accidents on Two-lane Rural Roads in Finland. Report 59/1992. Helsinki: The Finnish National Road Administration Technical Development Center.

Kjellén, U. 1984. The deviation concept in occupational accident control. Part I: Definition and classification; Part II: Data collection and assesment of significance. Accident Anal Prev 16:289–323.

Kjellén, U and J Hovden. 1993. Reducing risks by deviation control—a retrospection into a research strategy. Saf Sci 16:417–438.

Kjellén, U and TJ Larsson. 1981. Investigating accidents and reducing risks—a dynamic approach. J Occup Acc 3:129–140.

Last, JM. 1988. A Dictionary of Epidemiology. New York: Oxford University Press.

Lehto, MR. 1992. Designing warning signs and warning labels: Part I—Guidelines for the practitioner. Int J Ind Erg 10:105–113.

Lehto, MR and D Clark. 1990. Warning signs and labels in the workplace. In Workspace, Equipment and Tool Design, edited by A Mital and W Karwowski. Amsterdam: Elsevier.

Lehto, MR and JM Miller. 1986. Warnings: Volume I: Fundamentals, Design, and Evaluation Methodologies. Ann Arbor, MI: Fuller Technical Publications.
Leplat, J. 1978. Accident analyses and work analyses. J Occup Acc 1:331–340.

MacKenzie, EJ, DM Steinwachs, and BS Shankar. 1989. Classifying severity of trauma based on hospital discharge diagnoses: Validation of an ICD-9CM to AIS-85 conversion table. Med Care 27:412–422.

Manning, DP. 1971. Industrial accident-type classifications—A study of the theory and practice of accident prevention based on a computer analysis of industrial injury records. M.D. Thesis, University of Liverpool.

McAfee, RB and AR Winn. 1989. The use of incentives/feedback to enhance work place safety: A critique of the literature. J Saf Res 20:7-19.

Mohr, DL and D Clemmer. 1989. Evaluation of an occupational injury intervention in the petroleum industry. Accident Anal Prev 21(3):263–271.

National Committee for Injury Prevention and Control. 1989. Injury Prevention: Meeting the Challenge. New York: Oxford University Press.

National Electronic Manufacturers Association (NEMA). 1982. Safety Labels for Padmounted Switch Gear and Transformers Sited in Public Areas. NEMA 260. Rosslyn, VA: NEMA.

Occupational Health and Safety Administration (OSHA). 1985. Specification for Accident Prevention Signs and Tags. CFR 1910.145. Washington DC: OSHA.

—. 1985. [Chemical] Hazard Communication. CFR 1910.1200. Washington DC: OSHA.

Occupational Injury Prevention Panel. 1992. Occupational injury prevention. In Centers for Disease Control. Position Papers from the Third National Injury Control Conference: Setting the National Agenda for Injury Control in the 1990s. Atlanta, GA: CDC.

Organization for Economic Cooperation and Development (OECD). 1990. Behavioural Adaptation to Changes in the Road Transport System. Paris: OECD.

Rasmussen, J. 1982. Human errors. A taxonomy for describing human malfunction in industrial installations. J Occup Acc 4:311–333.

Rasmussen, J, K Duncan and J Leplat. 1987. New Technology and Human Error. Chichester: Wiley.

Reason, JT. 1990. Human Error. Cambridge: CUP.

Rice, DP, EJ MacKenzie and associates. 1989. Cost of Injury in the United States: A Report to Congress. San Francisco: Institute for Health and Aging, University of California; and Baltimore: Injury Prevention Center, The Johns Hopkins University.

Robertson, LS. 1992. Injury Epidemiology. New York: Oxford University Press.

Saari, J. 1992. Successful implementation of occupational health and safety programs in manufacturing for the 1990s. J Hum Factors Manufac 2:55–66.

Schelp, L. 1988. The role of organizations in community participation—prevention of accidental injuries in a rural
Swedish municipality. Soc Sci Med 26(11):1087–1093.

Shannon, HS. 1978. A statistical study of 2,500 consecutive reported accidents in an automobile factory. Ph.D. thesis, University of London.

Smith, GS and H Falk. 1987. Unintentional injuries. Am J Prev Medicine 5, sup.:143–163.

Smith, GS and PG Barss. 1991. Unintentional injuries in developing countries: The epidemiology of a neglected problem. Epidemiological Reviews :228–266.

Society of Automotive Engineers (SAE). 1979. Safety Signs. SAE J115: SAE.

Steckler, AB, L Dawson, BA Israel, and E Eng. 1993. Community health development: An overview of the works of Guy W. Stewart. Health Educ Q Sup. 1: S3-S20.

Steers, RM and LW Porter.1991. Motivation and Work Behavior (5th ed). New York: McGraw-Hill.

Surry, J. 1969. Industrial Accident Research: A Human Engineering Appraisal. Canada: University of Toronto.

Tollman, S. 1991. Community-oriented primary care: Origins, evolutions, applications. Soc Sci Med 32(6):633-642.

Troup, JDG, J Davies, and DP Manning. 1988. A model for the investigation of back injuries and manual handling problems at work. J Soc Occup Med 10:107–119.

Tuominen, R and J Saari. 1982. A model for analysis of accidents and its applications. J Occup Acc 4.

Veazie, MA, DD Landen, TR Bender and HE Amandus. 1994. Epidemiologic research on the etiology of injuries at work. Ann Rev Pub Health 15:203–21.

Waganaar, WA, PT Hudson and JT Reason. 1990. Cognitive failures and accidents. Appl Cogn Psychol 4:273–294.

Waller, JA. 1985. Injury Control: A Guide to the Causes and Prevention of Trauma. Lexington, MA: Lexington Books.

Wallerstein, N and R Baker. 1994. Labor education programs in health and safety. Occup Med State Art Rev 9(2):305-320.

Weeks, JL. 1991. Occupational health and safety regulation in the coal mining industry: Public health at the workplace. Annu Rev Publ Health 12:195–207.

Westinghouse Electric Corporation. 1981. Product Safety Label Handbook. Trafford, Pa: Westinghouse Printing Division.

Wilde, GJS. 1982. The theory of risk homeostasis: Implications for safety and health. Risk Anal 2:209-225.

—. 1991. Economics and accidents: A commentary. J Appl Behav Sci 24:81-84.

—. 1988. Risk homeostasis theory and traffic accidents: propositions, deductions and discussion of dissemsion in recent reactions. Ergonomics 31:441-468.

—. 1994. Target Risk. Toronto: PDE Publications.

Williamson, AM and A-M Feyer. 1990. Behavioural epidemiology as a tool for accident research. J Occup Acc 12:207–222.

Work Environment Fund [Arbetarskyddsfonden]. 1983. Olycksfall i arbetsmiljön—Kartläggning och analys av forskningsbehov [Accidents in the work environment—survey and analysis]. Solna: Arbetarskyddsfonden