Chemical Agent Use in Terrorist Events: A Gathering Storm Requiring Enhanced Civilian Preparedness

The use of chemical weapons in terrorist attacks, though rare, remains a significant challenge and concern due to their ability to inflict mass casualties. Chemical attacks remain a topic of interest for Disaster Medicine (DM) and Counter-Terrorism Medicine (CTM) specialists and are clearly an area in need of enhanced preparedness. This study aims to provide an epidemiological description of all terrorism-related attacks using chemical agents as a primary weapon, sustained from 1970 - 2019. These data will be useful in the development of education programs in CTM and provide an insight into how best to prepare for potential attacks in the future.

Data collection was performed using a retrospective database search through the Global Terrorism Database (GTD). The GTD was searched using the internal database search functions for all events using chemical weapons as a primary attack method from January 1, 1970 - December 31, 2019. Years 2020 and 2021 were not yet available at the time of the study. The GTD also details the specific chemical used, when known, in the summary of incidents. Results were exported into an Excel spreadsheet (Microsoft Corp.; Redmond, Washington USA) for analysis.

A total of 292 terrorist attacks involving chemical agents as a primary attack method were recorded from 1970 - 2019, registering 284 deaths and 13,267 injuries. Acid (52) was the most commonly used chemical agent, followed by "unspecified poison" (43), "unknown chemical agents" (29), "unspecified gas" (27), tear gas (27), chlorine gas (24), cyanide (21), mercury (9), pepper spray or mace (9), mustard gas (8), insecticide or 1080 (8), diphenylamine chloroarsine (7), phosphate or phosphorous (3), sodium hydroxide or corrosive liquid (3), sarin (2), "unspecified drugs" (2), VX nerve gas and other nerve gas (2), pesticides (2), cleaning chemicals/paint thinner (2), ammonia (2), anesthesia agent (1), arsenic (1), chlorine and mustard gas mix (1), phenarsazine chloride (1), rat poison (1), unknown irritative gas (1), hydrochloric acid and sodium cyanide mix (1), unknown white powder (1), antiseptic dye (1), and chlorine gas and white phosphorous mix (1).

The use of chemical weapons in warfare, though prohibited by the Chemical Weapons Convention (CWC), remains a rare but concerning terrorist attack methodology. In recent years, there have been more instances where potentially deadly chemicals have been used in civilian settings. Dual use industrial chemicals, in particular, pose a significant concern. Acid was the most commonly used chemical weapon in 52 attacks. Tear gas, chlorine, and cyanide were each used in over 20 attacks. Both DM and CTM specialists advocate for better preparedness and response training for intentional events in civilian settings.