Bought some drain cleaner from my local hardware store, the guy at the counter said its powerful stuff that barbers use to clear hair from drains. Said to not put my head above the drain while using it or breathe it in (standard for most household chemicals), open a window and use about 150ml, let it sit 5-10 mins then rinse with cold water, simple enough.
Go to use the stuff today on a tub/shower drain. I'd just finished a shower and got dressed, so there could have been some residual lukewarm water in the drain. As soon as I tipped the stuff into the drain, it bubbled violently and created some reddish-orange stains around the drain (since rinsed off) and some dark grey staining on the drain ring itself. Frantic googling revealed that it was sulfuric acid.
I started running cold water from the tap about 15 seconds after this reaction (googling while water was running) since that was the advice in the first place and rinsed the inside of the tub with cold water numerous times from a bucket and with detachable shower head, rinsing even the walls next to the shower that were most likely not even in contact with the bubbling drain (though there was some steaming and spitting, so something could have spattered).
the Window was open and I didn't smell anything during or after. I left the cold water run for about 5 minutes after the initial use, and checked on the thing and run water a few more times and aside from the dark grey staining, everything seems to be normal. It was sulfuric acid it turns out. If I had to guess - I would say I got maybe somewhere between 1-2 ounces/30-60ml (if that) out of the bottle. The reaction was so immediate that I stopped right away.
I live in a foreign country and can't read all labeling which is why I got the full download from the gent at the hardware store. Wasn't warned to expect bubbling/boiling so make sure all the water was cleared from the drain or wear PPE so guessing that's what caused the initial violent reaction. I did not use gloves or glasses - very stupid I know, but I would not have used the solution at all if I'd known. I did not get any on my skin but rinsed my hands many times regardless. I also threw some baking soda down after I'd rinsed the tub out many times and run the water for a very long time (that was probably at least 60-90 mins after initial use). Putting the soda down did not generate any reaction aside from absorbing water. nonetheless I scooped it out after about 45 mins bagged it a put it in the trash outside.
I called poison control about potential exposure on skin/inhalation - they said if it were there, I'd know by now (approx 45 - 60 mins after initial use), but based on the situation its likely that there was no exposure. I even changed and washed my clothes and my towel and bathmats that were nearby just in case (as was recommendation on many chem company websites/MSDS)
I won't be using any more of the acid, but is there anything else I should do to clean/clear the acid that was used? I immediately capped the bottle and set it down on the tile near the tub - but if there were a drop or two that happened on the tile or floor, what danger could that bring.
I'm freaking out a bit about how I was no naive and did not take the time to translate the label. Wondering if there are any future dangers to consider if its left in small amounts on the surfaces around the drain? most of the MSDS are geared toward severe spills/exposure/inhalation rather than smaller applications.