Wow. This is an incredible book. I have to admit, though, that I had some difficulty getting into Normal Accidents. There seemed an overabundance of detail, particularly on the nuclear industry's case history of calamity. This lost me, since I'm not familiar with the particulars of equipment function and malfunction. The book was mentioned, however, by two others of a similar nature and mentioned with such reverence, that after I had finished both, I returned to Perrow's book, this time with more success.
Professor Perrow is a PhD in sociology (1960) who has taught at Yale University Department of Sociology since 1981 and whose research focus has been human/technology interactions and the effects of complexity in organizations. (His most recent publication is the The AIDS disaster : the Failure of Organizations in New York and the Nation, 1990.)
In Normal Accidents, he describes the failures that can arise "normally" in systems, ie. those problems that are expected to arise and can be planned for by engineers, but which by virtue of those planned fail-safe devices, immeasurably complicate and endanger the system they are designed to protect. He describes a variety of these interactions, clarifying his definitions by means of a table (p. 88), and a matrix illustration (p. 97). Examples include systems that are linear vs complex, and loosely vs tightly controlled. These generally arise through the interactive nature of the various components the system itself. According to the matrix, an illustration of a highly linear, tightly controlled system would be a dam. A complex, tightly controlled system would be a nuclear plant, etc.
The degree to which failures may occur varies with each type of organization, as does the degree to which a recovery from such a failure is possible. As illustrations, the author describes failures which have, or could have, arisen in a variety of settings: the nuclear industry, maritime activities, the petrochemical industry, space exploration, DNA research and so on.
The exciting character of the stories themselves are worth the reading; my favorite, and one I had heard before, is the loss of an entire lake into a salt mine. More important still is the knowledge that each imparts. Perrow makes abundantly apparent by his illustrations the ease with which complex systems involving humans can fail catastrophically. (And if Per Bak and others are correct, almost inevitably).
Probably the most significant part of the work is the last chapter. After discussing the fallibility of systems that have grown increasingly complex, he discusses living with high risk systems, particularly why we are and why it should change. In a significant statement he writes, "Above all, I will argue, sensible living with risky systems means keeping the controversies alive, listening to the public, and recognizing the essentially political nature of risk assessment. Unfortunately, the issue is not risk, but power; the power to impose risks on the many for the benefit of the few (p. 306)," and further on, "Risks from risky technologies are not borne equally by the different social classes [and I would add, countries]; risk assessments ignore the social class distribution of risk (p. 310)." How true. "Quo Bono?" as the murder mystery writers might say; "Who benefits?" More to the point, and again with that issue in mind, he writes "The risks that made our country great were not industrial risks such as unsafe coal mines or chemical pollution, but social and political risks associated with democratic institutions, decentralized political structures, religious freedom and plurality, and universal suffrage (p. 311)." Again, very true.
Professor Perrow examines the degrees of potential danger from different types of system and suggests ways of deciding which are worth it to society to support and which might not be. These include categorizing the degree and the extent of danger of a given system to society, defining the way these technologies conflict with the values of that society, determining the likelihood that changes can be made to effectively alter the dangerous factors through technology or training of operators, and the possibility of placing the burden of spill-over costs on the shoulders of the institutions responsible. The latter might conceivably lead to corrective changes, either by the institutions themselves in order to remain profitable or by consumers through purchasing decisions.
The bibliography for the book is quite extensive and includes a variety of sources. These include not only popular books and publications on the topics of individual disasters, but government documents, research journals, and industry reports as well. I did not find any reference to the Johnstown flood, my particular favorite dam burst story, but there are a wide variety of references to chose from should someone wish to do their own research on the topic.
Altogether a fascinating and informative book.