Modelling the Seveso disaster

At the time of the Seveso disaster, the complexity of communication problems under conditions of severe uncertainty was recognized, if not fully managed. Before the gas release, no one outside the plant neither residents nor political or health authorities - had any idea that there was a hazard of such magnitude. The explosion and release were greeted by incredulity, followed by alarm and dismay. The firm's initial behaviour led to subsequent suspicion about their motives; various instructions for precautionary measures were issued almost immediately, but the firm denied knowledge of the toxic substances involved (Rocca 1980; Rocca 1992, personal communication). Ten days passed before the firm confirmed that dioxin had been released (Pocchiari, Silano, and Zapponi 1987). Only then did the governmental authorities and the public learn that there was a grave risk. Even so, it was impossible to assess the danger with any precision. There was an onset of genuine dread, about illness in general and about malformed babies in particular. The widespread illness and deaths of animals of many species was an ominous sign. The authorities had their own severe problems of decision-making under uncertainty, including the definition of different polluted zones, programmes of evacuation of endangered residents, and disposal of contaminated material.

From the very beginning of the disaster, situational uncertainty was salient; decisions had to be taken, sometimes under conditions of great urgency' in the nearly complete absence of information that might guide actions. Scientific uncertainty was salient, as shown by the fact that local investigating magistrates closed off the site within eight days of the accident. Societal uncertainty was severe because there had been no previous institutional preparation or consultation for the accident. Legal/moral uncertainty was also severe. For example, the (Swiss) Technical Director of ICMESA found himself under arrest when he attended a works meeting 12 days after the accident (the Director of Production was also placed under arrest at that time, and was assassinated by terrorists four years later). One of the few relatively straightforward aspects of the accident was the low level of proprietary uncertainty. Although the provision of relevant information did not proceed as quickly or smoothly as desired by all, at least there was no need for the government authorities to use legal means to force the firm to divulge information. The fact that the ICMESA factory was already sequestered would have made it highly imprudent for its owners to withhold information about the contaminants, and it was noted at the time that the dioxin threat had already been publicized by the media before it was officially confirmed. Later, and off the Seveso site, proprietary uncertainty was not as low, particularly in connection with the disposal of barrels containing toxic materials. From 1982 onwards, stories of concealment and blunders began to circulate and these have not yet ended (see Chronology).