These calculations seem always a bit odd- what does it mean to "have the potential to kill thousands"? It was used in a highly populated area, was handled without any special care, and killed exactly one person.<p>I also have a brick that has the potential to kill thousands, if you use it repeatedly to crush people's skulls.
It could kill thousands, but only sickened the people it was actually (professionally) used against.<p>Its so secret no one knows exactly what it is, but happily one of the few people around able to recognize it was the person to discover it.<p>There's quite a lot of open questions around this case that could benefit from further data.