Advanced Safety Management, 3rd Edition

CHAPTER 23JAMES REASON'S SWISS CHEESE MODEL

In recent years, no individual has had more influence on how people think about incident causation than James Reason. In Managing the Risks of Organizational Accidents, Reason (1997) wrote about two ways that systems could be disrupted. He recognized that active errors, what have been called unsafe acts, could be committed by operators and be the initiator for an incident. But he also emphasized that what he labeled latent conditions could be resident in an operation for some time.

Reason emphasized that latent conditions are present in all organizations; result from decisions made by “manufacturers, designers and organizational managers”; and could be the more significant causal factors for accidents. His views on the origins on latent conditions have had a major impact on the thinking of many safety professionals. (p. 10)

My interpretation of what Reason wrote about latent conditions fits particularly well with the citations that were taken from Guidelines for Preventing Human Error in Process Safety (1994) and appear in Chapter 8 on “Human Error Avoidance” in this book. Authors of the Guidelines book recognized that failures at the management, design, or technical expert levels of the company could result in adverse situations (p. xiii) and that organizational factors could create the preconditions for errors, as well as being the immediate causes of incidents. (p. 5)

HOW EXTENSIVE IS THE USE OF THE SWISS CHEESE MODEL?

Only ...