Fermentation chamber gasses

I bought a chest freezer and made a temp controller for my last 2 batches.

Brewed a 1.068 stout and used WLP013. Nice, aggressive fermentation out airlock, so changed to a 1" blowoff tube. 2 days later (today), I go to put the airlock back on and there is such a potent (ammonia like) gas smell that it burns my eyes when I stick my head in the chest freezer. Is this a sign of rotting or maybe that the regular gasses of fermentation are locked up in the freezer?

I worry because even though I sanitized when I pulled the 1" hose out there is a chance of something getting in and if this smell is a known issue I may be in trouble.

Does it burn your nose when you inhale? I'm guessing it does, which means it's actually CO2! You're fine.

Probably just the CO2 from the fermenter. I have a freezer as well for my lagers and I don't dare stick my head in there.

Yes, it burns!!!! Why can't I stop sniffing. I'm so light headed!!

Awesome - sounds like it's supposed to be that way. Thanks guys!