It happend on 20 March 1995, during rush hour. It killed 13 people, severely injuring 50 (some of whom later died) and causing temporary vision problems for nearly 1,000 others. Its leader, whose name I’m not gonna mention (you can read it if you want), was executed on July 6, 2018 by hanging.
The same cult previously tried using botulinum, the lethal dose of which is approximately fucking nothing. All anyone reported was a bad odor. It is simply a pain in the ass to weaponize most biochemicals.