Heinrich domino

BOS 4601, Accident Investigation 1

Course Learning Outcomes for Unit II Upon completion of this unit, students should be able to:

5. Compare various accident causation theories and models. 5.1 Relate accident causation theories and models to accident scenarios.

Reading Assignment Chapter 3: A Short History of Accident Theory In order to access the resource below, you must first log into the myCSU Student Portal and access the Business Source Complete database within the CSU Online Library. Manuele, F. A. (2014). Incident investigation: Our methods are flawed. Professional Safety, 59(10), 34-43. The following work can be found on the Internet by typing the title into a search engine or clicking on the link provided: Toft, Y., Dell, G., Klockner, K., & Hutton, A. (2012). Models of causation: Safety. Retrieved from

http://www.ohsbok.org.au/wp-content/uploads/2013/12/32-Models-of-causation-Safety.pdf?ce18fc

Unit Lesson Why do accidents happen? What needs to be done to prevent accidents from happening? These two questions are at the heart of any organization’s accident prevention efforts. Unfortunately, there is no simple answer. Some may even say that there is no answer at all. Remember that the various definitions of an accident include words like “unplanned” and “unanticipated.” Can we really identify ways to prevent something from happening that we cannot (or did not) anticipate? The accident investigation process gives us the opportunity to learn what went wrong. The worldwide body of knowledge related to accident causation has been a significant contributor to accident prevention efforts. Before an attempt is made to investigate an accident, it is helpful to have a better understanding of how—not why—accidents happen. Analysis of accidents over the last century has led to a number of theories and models of accident causation. One the earliest theories came from H. W. Heinrich in the 1930s (Oakley, 2012; Toft, Dell, Klockner, & Hutton, 2012b). Heinrich postulated that accidents are caused by unsafe acts, unsafe conditions, or some combination of these. According to Heinrich, unsafe acts represented 80% of the causal factors, and unsafe conditions represented 20% (Oakley, 2012). More than 80 years later, this theory is still applied by many safety practitioners. Indeed, you can see it reflected in the way the Occupational Safety and Health Administration (OSHA) addresses workplace safety: OSHA standards contain prescriptive guidelines to control workplace hazards (unsafe conditions). OSHA standards also contain training and operational guidelines to modify or control worker behavior (unsafe acts). In the latter part of the 20th century, the behavior-based safety (BBS) movement further increased focus on controlling unsafe acts. Heinrich expanded on his unsafe acts/unsafe conditions theory and incorporated it into a representation, or model, of the accident sequence. He described the accident sequence as a series of dominos. If one domino (causal factor) is removed, the accident will not happen. Heinrich’s domino theory has been updated and modified over the years, but its use remains pervasive. Undoubtedly, its use has resulted in many improvements to the accident investigation process.

UNIT II STUDY GUIDE

Accident Causation Theory

BOS 4601, Accident Investigation 2

UNIT x STUDY GUIDE

Title

The domino theory is an example of a simple linear model of accident causation (Toft et al., 2012b). It is simple, in that it is a single series of events, and linear, in that the events happen in sequence. It has been shown, however, that there are often multiple linear events that converge, resulting in an accident. In response, several complex linear models have been developed, such as the time sequence model, the epidemiologic model, and the energy damage model. In the 1990s, the focus of accident modeling shifted from unsafe acts and unsafe conditions to a broader approach, which involves the interactions among people, their equipment, work processes, and