From Eric Kvaalen
Debora MacKenzie says it is unlikely that there will be chemical and biological attacks by terrorists (28 November, p 30). But there have been incidents apart from the Aum Shinrikyo cult’s attacks with home-made sarin in Japan (11 May 1996, p 3), which she mentions. For example, there by the followers of the guru Rajneesh, involving salmonella.
Islamic State is a more powerful group than either, and has attracted many skilled engineers from all over the world.
Les Essarts-le-Roi, France
