I worked for an aerospace company in the mid 80s and recall the metallurgy shop using cyanide in some metal hardening process. Very closely guarded. I didn't know it was there until an earthquake when the local fire / hazmat people showed up and took care of it.
I always intended to go see how it was stored, but never found the time before I got laid off.
Anyone seen such a storage system? I know it was in stainless tanks about 80 yards from the back of the plant, surrounded by concrete walls, but nothing more.
