Apparently it isn't the bleach that is the issue in itself. The cleaners are supplied with latex gloves. Cleaning and flushing thru to dispose of the bleach would nominally suffice. But even 3 4 5 6 7 litre flushes wouldn't dispose of allo the bleach. (you know.... curry night before and floater issue!) It's the addition of other chemicals that would interact with bleach and give off noxious fumes. Health and saftey and duty of care issues regarding mixing chemicals is the issue. So, when I light up a ciggy and the smoke alarm doesn't go off, but when I solder a joint and the smoke alarm goes mental I have to make sure that I inform the monitoring agency to temporarilly disable the alarms.... lest the FB come a charging... sirens ablazing!