Like usual, this didn't actually happen today, but a while ago.
My first job was working at a local pizza place, it was really chill to the point where it was pretty common for employees to be drunk and/or high while on the clock.
One night, I (as the youngest on shift) was left to mop up the back room while everyone else was chilling on the patio for a bit since we were pretty much done for the night.
Its pretty late at this point so I'm trying to fill up the bucket so I can start,
and I see a couple of the many spray bottles we have lying around that are always full of some really mild cleaning solution.
I was impatient and figured our mild cleaning solution would be fine mixed with bleach (which is what we were using on the floor) so I dumped the bottles in in an effort to fill
the bucket faster.
Buckets full, dump in bleach, begin to mop.
A few minutes in, I start to notice that I'm feeling a bit lightheaded and nauseous, but I figure its just because I've been working for almost eight hours at this point without an actual break.
It's been probably 20 minutes or so since I was sent back to mop so one of my coworkers came back to check on me and they immediately noticed something was wrong, yell something about the smell.
Mutual realization that something is definitely Wrong.
Check the bottles, turns out I accidentally managed to find the one solitary bottle of vinegar thats used to scrub the oven and dumped that in with my bleach, thus making chlorine gas.
Ended up having to air out the entire restaurant for probably 40 minutes. Luckily my manager thought it was kind of funny and was glad I didn't accidentally kill us.
tl;dr accidentally waged chemical warfare in restaurant kitchen
edit: a lot of people are saying something along the lines of "never mix cleaning products dumbass!
" yeah i know i passed high school chemistry too; i was a tired 17 year old and i thought i was adding hella diluted dish soap (which i had seen be added before with absolutely no ill effects),
not the one singular spray bottle of vinegar