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close this bookThe Long Road to Recovery: Community Responses to Industrial Disasters (UNU, 1996, 307 p.)
close this folder4 Seveso: A paradoxical classic disaster
close this folderOverview
View the documentThe chemical release
View the documentDioxin
View the documentThe Seveso Directive

The chemical release

Around midday on Saturday 10 July 1976, an explosion occurred in a TCP (2,4,5-trichlorophenol) reactor of the ICMESA chemical plant on the outskirts of Meda, a small town about 20 kilometres north of Milan, Italy.1 A toxic cloud containing TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin), then widely believed to be one of the most toxic man-made chemicals (Mocarelli et al. 1991), was accidentally released into the atmosphere. The dioxin cloud contaminated a densely populated area about six kilometres long and one kilometre wide, lying downwind from the site (fig. 4.1). This event became internationally known as the Seveso disaster, after the name of a neighbouring municipality that was most severely affected (Hay 1982; Pocchiari, Silano, and Zapponi 1987).

Fig. 4.1 Area affected by the Seveso dioxin release (Source: Roche Magazin 1986)

Eleven communities in the rolling countryside between Milan and Lake Como were directly involved in the toxic release and its aftermath. The four most impacted municipalities included Seveso (1976 population 17,000), Meda (19,000), Desio (33,000), and Cesano Maderno (34,000). Two other municipalities were subject to postaccident restrictions: Barlassina (6,000) and Bovisio Masciago (11,000). Health monitoring was extended to a further five municipalities. The entire affected area is part of the Brianza, a prosperous district of Lombardy, itself one of the wealthiest and most industrialized regions of Italy (fig. 4.2). Though originally agricultural, the economy of this area depended on a cluster of small workshops and industries, mainly engaged in manufacturing furniture.

The Seveso disaster had a particularly traumatic effect on exposed local populations because its seriousness was recognized only gradually. The community was divided by rancorous conflicts. People in other countries also experienced much heightened concern about industrial risks and the need for tighter regulation of hazardous chemical installations. In these respects Seveso resembled Bhopal (1984) and Chernobyl (1986), which have both come to be regarded as international symbols of industrial pathology.

Fig. 4.2 Location of Seveso

But as we shall see, Seveso is a paradoxical symbol, because human health effects of the disaster have been obscure and the process of recovery has been unusual. Victims have been compensated, workers have been redeployed, a substantial programme of long-term health monitoring is in operation, and the site itself has been made into a park. Though initially slow and conflicted, responses to the accident may eventually have showed high-technology society working at its best. Recovery was therefore a process of overcoming initial traumas (e.g. chloracne, fear of genetic impairments, evacuation, animal deaths) and re-establishing customary patterns of societal, economic, and institutional life.

For some, the main lesson of Seveso might be that a reasonably prompt, effective, and generous response by public and private agencies is the key to community recovery. But, to a significant degree, local recovery was achieved by exporting parts of the problem. Seriously contaminated materials were disposed of abroad in an atmosphere of confusion and scandal; their ultimate fate is still unravelling (Gambino, Gumpel, and Novelli 1993; see also Chronology items December 1992 and November 1993). This, too, is part of the style of high-technology industry: consumer satisfaction is often sustained by "externalizing" environmental costs and attendant social problems. In other words, the burdens of technology are often transferred away from producers and immediate consumers into a universally shared but unprotected natural environment or into specific poor communities (local or overseas) that are treated as sweatshops and dumps.2


The Seveso experience was essentially about dread - an emotion mobilized by involvement of the chemical dioxin. Dioxin first came to widespread public notice during the Viet Nam War, when it was identified as a component of the defoliant Agent Orange (Hay 1982). Previously, campaigns on behalf of agricultural and forestry workers had been mounted to have TCP banned because of its alleged toxic effects on humans. These frequently met with scientific disapproval, partly because the evidence was only "anecdotal." The United Kingdom's regulatory system was particularly unsympathetic to such claims (Wynne 1989).

Before the Seveso release, several industrial accidents involving TCP were known to have occurred. Among others, these affected the following firms and countries:

· 1949 Monsanto (USA);
· 1953 BASF (Germany);
· 1960 Dow Chemical (USA);
· 1963 Phillips Duphar (Netherlands);
· 1968 Coalite Chemical Productions (UK).

These accidents precipitated acute illness among affected workers and added to the burden of existing chronic sickness caused by prolonged exposure to the same chemicals under unsanitary conditions (Hay 1982: 138140). After the BASF accident, production of TCP was stopped at that site. The same occurred at Phillips Duphar, where the plant was closed and subsequently dismantled; its pieces were swathed in concrete and dumped in the Atlantic Ocean. Similar procedures were adopted at the Coalite site near Bolsover. After the Dow Chemical accident, new installations were constructed there. The reactor was enclosed by a supplemental safety vessel, whose purpose was to collect and cool any toxic material that might leak if reactor valves ruptured (Otway and Amendola 1989). Similar "containment vessels" have been widely employed in nuclear power stations that house pressurized water-cooled reactors. Had there been such a vessel at ICMESA, there would probably have been no Seveso disaster.

Dioxin was known to be an extremely dangerous substance, partly because of these industrial experiences and partly because experimental evidence indicated that it was unprecedentedly toxic to some species of laboratory animals. In many ways the image of dioxin was similar to that of radioactivity: it was invisible, it poisoned at microscopic dose levels, and it was implicated in war. Moreover, because dioxin was carried by people and things, it took on the appearance of a dread disease - a plague. In particular, it was the sense of being gravely contaminated that increased personal, social, and economic distress among the affected population. Products of dioxin-impacted areas were rejected because of feared contamination, thus imposing a stigma on whole communities.

The Seveso Directive

The best-known consequence of the Seveso disaster was the impulse that it gave to the creation of the European Community's Seveso Directive, a new system of industrial regulation. Within the EC, each country previously followed its own rules for managing industrial safety. Urgent discussions about a new EC-wide regulatory framework for ensuring the safety of hazardous installations started after an explosion of cyclohexane in the Nypro Ltd. plant at Flixborough (United Kingdom, 1974).3 During the next two years, three additional serious chemical accidents occurred within the European Community: these were at Beek (the Netherlands 1975), Manfredonia (Italy 1976), and finally Seveso (Otway and Amendola 1989; Drogaris 1991).

One of the most remarkable features of the Seveso experience was that neither the residents nor the local and regional authorities suspected that the ICMESA plant was a source of risk. They did not even know much about the type of production processes and chemical substances that occurred there. As the Mayor reported (Rocca 1992, personal communication), the factory had been in existence for 30 years and the only occasional complaints from nearby residents concerned some unpleasant smells. Moreover, at Seveso as well as Flixborough, "changes had been made in plant or processes which compromised the safety of the facilities but were not communicated to authorities responsible for public health and safety" (Otway and Amendola 1989: 507).

In light of these disastrous accidents it was clear that new legislation was needed to improve the safety of industrial sites, to plan for off-site emergencies, and to cope with broader regional and transboundary aspects of industrial safety. The Seveso Directive, adopted by the Council of Ministers of the European Communities in June 1982 (Directive 82/501/EEC), is the result of those efforts. A central part of the Directive is a requirement for public information about major industrial hazards and appropriate safety measures in the event of an accident. It is based on recognition that industrial workers and the general public need to know about hazards that threaten them and about safety procedures. This is the first time that the principle of "need to know" has been enshrined in European Community legislation. The "need to know" principle is not as strong as the "right to know" principle that is widely applied in the United States. The status of "need" is determined by the authorities; it is not a right of citizens (Baram 1991; Royal Society Study Group 1992).

Although the Seveso Directive grew out of deficiencies in the existing system of industrial regulation, it is not simply intended to provide protection against hazards: it is also designed to equalize the burden of regulation on industry. The creation of a single hazardous industry code ensures a "level playing field" for trade within the European Community by depriving unscrupulous industrial operators of competitive advantages that might flow from exploiting differences among varied national regulations. Moreover, adoption of the "need to know" principle increases the political equity of decision-making and adds a valuable new tool to the regulatory process. The next section examines this institutional response in greater detail.