[jandrewrogers]

Synthesizing high explosives from anhydrous ammonia is not trivial and no random person would ever bother. There are easier precursors to work with and much easier ways to acquire high explosives than trying to bootstrap from ammonia.

And if someone really was bent on mayhem, well, anhydrous ammonia is nasty toxic stuff as is. You don’t need to do anything chemically to it to kill or injure a lot of people. On the other hand, it isn’t a chemical that sneaks up on you. If you are being exposed to dangerous levels, you’ll know it.