- Release of toxic/flammable materials
ICMESA Chemical Company, Seveso, Italy, 10 July 1976
Rupture of the bursting disc on batch plant for the manufacture of 2,4,5-trichlorophenol (TCP) led to the release of highly toxic dioxin. Dioxin is not normally formed but the reactor got too hot resulting in a runaway reaction which caused a rise in pressure leading to the disc rupture.
The maintenance staff heard a whistling sound and a cloud of vapour was seen to issue from a vent on the roof giving rise to the formation of a dense cloud of considerable altitude. The release lasted some 20 min.
- Plant Siting
Housing developments had been built around the area after the plant had been established.
- Acquisition of companies operating hazardous processes
The management of the company ultimately responsible for the plant was not familiar with the hazards. The latter company owned a second company which itself owned ICMESA.
- Hazard posed by ultratoxic substances
Ultratoxic substances need to be well understood and the risks properly managed
- Failure to adhere to operating procedures
- Planning for emergencies
Information on the chemical released and its hazards was not immediately available from the company. Communication between the company and the regulatory authorities was inadequate which resulted in a failure to protect and communicate with the public.
- Safer reactor design
Safer design of reactors were also given greater priority after the accident.
The most important implication of the Seveso disaster is the impulse that it gave to the creation of a European Community directive for Major Accidents Hazards (1982).