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Swiss NBC scenarios

On the preparation of protection measures

Chemical plant accident, animal epidemic, radiological bomb: In order to get a systematic overview of the hazard potential of possible disasters and emergencies, organizations in charge of disaster management perform analyses of hazards or risks, respectively. This involves identifying the spectrum of possible hazards, developing specific scenarios, analyzing their impacts in a sophisticated manner, and assessing the likelihood of occurrence for the scenarios described. A scenario describes a possible course of events, which illustrates and best represents a certain category of potential hazards. In Switzerland, the bodies appointed to deal with NBC protection issues use these types of scenarios to develop and continually review the necessary NBC protection measures.

Foundations from the Federal Office for Civil Protection FOCP

The binding basis for implementing the „National NBC Protection“ project and the „Swiss NBC“ strategy were the NBC scenarios developed by the Spiez Laboratory (branch of the Federal Office for Civil Protection FOCP). Scenario risk assessment is based on a method that enables us to determine and compare with each other different risks according to a uniform procedure. This method was developed by the Risk Analysis / Research Coordination section of the FOCP.

Statistics and expert assessments

Information on likelihood and the effects of scenarios are based on the analysis of incidents, statistics, publications, other scenarios etc. Where information is missing – for instance if there are considerable uncertainties as to the extent of effects, the frequency of occurrence or the plausibility of scenarios – estimates are obtained through expert panel discussions. During these expert sessions, an interrogation method is used that is based on the Delphi procedure that provides for an efficient approximation and consolidation of assessments.

For naturally caused and technical dangers or attacks

The likelihood or frequency that a scenario arises is determined as precisely as possible for natural and technological hazards – on the basis of statistics or expert estimates. If scoring based on probability calculations is impossible, the likelihood is allocated to a probability class with a logarithmic scale. Deliberately caused incidents (e.g. attacks), cannot be described in terms of frequency. For such cases the plausibility of their occurrence is assessed for the coming ten years on the basis of subjectively assessed likelihood. Here things like technical feasibility of an attack, its impact and chances of success are assessed. If precedent cases exist, this is also taken into account. In analogy to the likelihood and frequency classes, deliberate incidents are assigned to a plausibility class.

Few scenarios

The number of scenarios has been limited. Never-the-less, they cover the range of threats and dangers well – from accidents and natural disasters to terror / sabotage and politic-military incidents. The following scenarios were developed:


  • Nuclear plant accident
    Radiological bomb
    Nuclear weapon explosion near the Swiss border
    Attack on a transport of highly radioactive waste


  • B-toxin attack
    Pathogen virus attack
    Anthrax attack
    Pandemic – new, yet unknown pathogen
    Pandemic – influenza
    Animal epidemic – outbreak of hoof-and-mouth disease in Switzerland


  • Transport attack or accident
    Chemical plant accident
    Toxin attack
    Chemical weapon attack
    Chemical weapon attack on Switzerland


  • Earthquake