Emergencies, outbreaks of disease, and chemical incidents have the potential to cause disruption for communities on a large scale. Disease outbreaks and chemical incidents can develop very rapidly - so preparation and emergency planning are essential components in minimising the impact on the public.

The growing threat of global terrorism means we need to be prepared to deal with incidents that could involve chemical, biological, and radioactive materials. This means new plans and new expertise. The classic scenario of WMD use against civilians (the basis for many current exercises) is the release of the nerve agent Sarin in the Tokyo subway. In this attack the actions of first responders and medical staff helped keep the final fatalities down to 12. The diversity and gravity of threats are exemplified by recent attacks on the US Congress through the postal system, it claimed few  victims, thanks to rapid intervention by bioweapons specialists, but it paralysed the postal system and cost over $6bn to clean up.