Sounds like Flying Dog is having some issues tonight. I've heard a couple of calls go our over the police scanner now, must be a pretty bad incident. Something about an active hazmat incident and a visible ammonia cloud. What would ammonia be used for? Refrigerant?
My guess would be a refrigerant - or they have switched over to making "pink slime."
Ammonia would not be an ingredient, and industrially, maybe it is used as a cleanser. Most breweries would be using a sanitizer that is more neutral and rinses cleanly, then something like ammonia which can be very 'vaporous'.
http://www.fredericknewspost.com/sections/news/displayUpdate.htm?StoryID=135566