Ammonia is still used as a refrigerant in large industrial plants, like on factory boats that process and freeze fish at sea. In a way, ammonia is nice because it tells you it's there. Unless there's a sudden break, you'll be out of the room long before ammonia will kill you, just because you can't stand to be there. On the other hand, the Freons can slowly displace oxygen and you can suffocate without knowing that there was a leak. Anhydrous ammonia is apparently used in meth production, because one of our clients had people trying to steal it from their spare tanks. One of the stupider ones drained some into a bucket and put a lid on. He didn't realize that the anhydrous would pull water out of the air, expand, and blow the lid off the bucket. They found him puking in the ditch about a hundred yards down the road.
The office used to have one of the ammonia blueline machines, but it's long gone. I do still like the nostalgic residual smell on old drawings, but people look at me funny when I say that.