I'll never forget when i was experimenting with producing free halogens from salts like potassium bromide or chloride using concentrated mineral acids. When I produced bromine I remember the reddish-brown vapours rolling off the table to the floor then across the floor and down the stairs....step by step. I stopped the reaction and told my brother to GET OUT OF THE HOUSE !! which is where we remained for a few hours till the fumes cleared away. When my Mom got home she remarked about that "clean sterile hospital-like smell" in the house. Even a couple weeks later you could still notice the faint smell of bromine. Guess it killed any germs hiding in the corners and crevices. Unfortunately I didn;t have a fume hood like they have in industrial or academic labs,