I'm a little late to respond but the best story I have is from another lab supervisor I spoke to. Wet minilabs all have an effluent tank that fills up with the spent chemicals. This is after a cartridge to collect all the silver.
Remember we call one of the chemicals 'bleach'. It's a bad name. This effluent tank usually gets dumped out in a sink near the lab when it's full or at the end of the day. I say that bleach is a bad name because C-41 process contains ammonium ferric PDTA, which I believe is pretty close to ammonium iron sulfate. (not a chemist)
Anyways, the store I mentioned had a mess that needed cleaning at the end of the day, so the kids got out cleaners containing bleach and mopped up the floor... then proceeded to dump the cleaner down the same sink as the effluent. This readily produced noxious fumes (possibly mustard gas) that forced a store evacuation. Store was closed for around 2 days as hazmat crews made sure the place was safe to go into.
Remember we call one of the chemicals 'bleach'. It's a bad name. This effluent tank usually gets dumped out in a sink near the lab when it's full or at the end of the day. I say that bleach is a bad name because C-41 process contains ammonium ferric PDTA, which I believe is pretty close to ammonium iron sulfate. (not a chemist)
Anyways, the store I mentioned had a mess that needed cleaning at the end of the day, so the kids got out cleaners containing bleach and mopped up the floor... then proceeded to dump the cleaner down the same sink as the effluent. This readily produced noxious fumes (possibly mustard gas) that forced a store evacuation. Store was closed for around 2 days as hazmat crews made sure the place was safe to go into.
Nobody was hurt but not a great look....