Mixing 5-9% solutions will still produce chlorine/chloramine gas and can cause significant lung damage. The maximum commercially available (sodium hypochlorite

Mixing 5-9% solutions will still produce chlorine/chloramine gas and can cause significant lung damage. The maximum commercially available (sodium hypochlorite) bleach concentration is about 15%, and that’s due to its non-linear rate of decomposition and extremely short shelf-life at higher concentrations. A 15% solution must be used very soon after manufacture and does not have significant non-industrial uses — that’s why it’s not stocked in grocery stores. It has nothing to do with its safety at that concentration. 100% bleach would be anhydrous sodium hypochlorite, which is highly unstable and can decompose explosively. Nobody stocks that.