Main Question or Discussion Point
I work at a pool, and to keep the pH constant (chlorine is a base I suppose), there is a vat of water and hydrochloric acid which is pumped into the pool when the pH reaches a certain level of basicness. Anyway, it ran out today and it's the lifeguard's (my) responsibility to re-fill the tank with water and add hydrochloric acid to it. When I did this, I noticed that there was a steam coming from the vat. I was careful to hold my breath and not inhale any of it, and was curious what exactly it was, and if I should be supplied with some sort of gas-mask for this task.