Comment by Suppafly

Farmers use anhydrous ammonia that bounds with water in the soil and then bonds to the soil.

I don't know that farmers wear anything special when applying it, but there are safety procedures. I work with a farmer and he was telling me about one time he forgot to switch one of the valves off and when he disconnected a hose, the fumes knocked him out. Luckily it was just the fumes from the hose and not the whole tank or he likely would have died instead of just being knocked out.