Since 2016, we began collecting daily tweets related to chemical, biological, radiological, and nuclear (CBRN) weapons. The collection is done automatically through an in-house script based on the twitteR package of R. The query used for the collection evolved over time and, at present, is formulated as indicated below. For practical reasons, for each pair of keywords – e.g. “chemical weapons,” “chemical attack” etc. – the maximum number of tweets to retrieve was confined to 25,000. From the ensemble of collected tweets, subsets containing the keywords “chemical,” “biological,” “radiological,” or “nuclear” were isolated in order to analyze the discourse on the four different CBRN domains. Notably, these subsets might be overlapping, in that the same tweet can fall within the scope of more than one subset – for instance a tweet may contain the words chemical and biological.

(chemical OR biological OR nuclear OR radiological) AND (attack
OR attacks OR bomb OR bombs OR missile OR missiles OR mortar or mortars OR
rocket OR rockets OR weapon OR weapons OR security OR terror OR terrorism OR threat
OR war OR wars OR warfare OR warhead OR warheads)