20 years ago, on the 20th March 1995, chemical weapons were misused by terrorists for the first time. It happened in the Tokio subway during morning rush hour. Members of Aum Shinrikyo cult launched nerve agent – sarin - at five subway stations. The consequences of attacks killed 12 people from more than 5,500 affected. Only the lack of basic knowledge and experience of the terrorists prevented a much greater loss of life. The incident, however, sent out a warning signal that something like this can happen anywhere.
Kasumigaseki station, one of the stations, in which sarin attack was carried out (Wikipedia)