This thing about Campden tablets...

[Hilary B]

I did a quick cursory trawl on the internet on campden tablets - it seems their efficacy is in killing any diffuse yeast at the time it is administered. The base of campden tablets i.e. sodium metabisulphate quickly loses it's strength in a matter of hours and so its chlorination effect/or whatever diminishes.

Having said that, I don't know if it was in the context of aerobic environs or anaerobic environs.

Sulphite/sulphur dioxide will (in sufficient concentration) kill micro-organisms (including yeast). This does not guarantee that a campden tablet will kill off all the yeast in a fermenting wine, nor that if the yeast present is killed off, that 'wild' yeast cannot get in and start it off again.
I know some of the chemistry, but NOT the relevant concentrations applicable to this situation.
Old winemaking techniques using wooden barrels used to include burning sulphur to 'fumigate' the barrel between batches.....
BTW, too much sulphur dioxide is bad for humans too.....