For scenarios involving chemicals with delayed health effects, active recognition may be the only means of recognizing the event unless the release itself is observed by the public, venue employees, or law enforcement.
The release of a chemical warfare agent or toxic industrial chemical in high-traffic areas such as transportation systems/hubs, sites of cultural or historic interest, sports/ entertainment venues, houses of worship, theaters, amusement parks, etc. is a national concern. For example, crowds of commuters and generally open security environments make transit venues, particularly transit terminals, airport ticketing areas, and subway systems, very attractive terrorist targets. Aum Shinrikyo’s 1995 attack in the Tokyo subway with the chemical warfare agent sarin demonstrates how vulnerable these targets are; the attack left 12 dead and affected thousands more.22 Recognizing that open access facility types represent potentially attractive targets, many such venues employ some variety of active chemical detection system. Such systems enable a coordinated, well-executed and quick response to a suspected chemical attack and can greatly limit the spread of the chemical substance and the resulting casualties. However, if the incident involves a chemical that is not one of those detected by the venue’s system, the incident may go unrecognized, or may require passive/ surveillance systems to facilitate incident recognition.
Footnotes
22. Levy, L., Smithson, A.E. (2000). Rethinking the Lessons of Tokyo. Ataxia: The Chemical and Biological Terrorism Threat and the US Response Stimson Report 35. (pp. 71-111). Global Health Security.