I nearly did.
Needed to clean the outdoor tiled entertainment area before the big move out. There are some tannin and rust stains on it, and seeing the tiles have an antislip coating, these are a pain to remove.
So, the backyard dodgy chemist in me lays downs some hydrochloric acid and start scrubbing with a stiff broom.
Well, I expect the HCl is reacting nicely with the calcium carbonate in the tile grout, and I am slowly enshrouded in chlorine or some variant thereof, considering the airflow in this area is nill at the best of times. WHOA!!!
Now, I am also assuming this concoction of halides is turning into hypochlorous acid or similar in my trachea, ripping mucousal membranes assunder, as in no time I am hacking up and vomiting. I cannot get away from it fast enough, but realise I HAVE to return to wash the bloody thing off and stop it from poisoning the known universe! I stood back with the hose a LONG way away and with a towel wrapped around my head.
For the next 12 hours I had rales and wheezes, continual spitting as my mucous membranes repaired, and a pain in my right lung, which only by the sheer luck of the Irish did NOT turn into a pulmonary oedema! I ALMOST rang 000, but didn't, and my wife watched me all night.
And I missed some good astronomy.
I had done this before, SUCCESSFULLY, but for some odd reason this one went awry - new brand of HCl (not Diggers as usual, got the Bondall one) and just bad luck and stupidity. Time will tell what damage was done, but for the second time in my life I really felt I would not make it through the night.