I recently attended the Atlanta Writers conference. I was asked one question multiple times. I reference VX, a highly lethal chemical weapon in my manuscript. I was repeatedly questioned if this is a real thing. Yes!
No seriously it exists, it is a manmade substance for one purpose and one purpose only to kill. It is a chemical nerve agent that has horrific side effects depending on the severity of exposure. Yes, a single drop can kill, however you can survive if you do the right things.