chlorinated shock from pool store BAD?

Purchased some packages of shock from a local pool store and when i got home i opened the box and the bags were so swelled up that i thought they were going to burst. so i returned them and the guy working said anyone with a basic science degree knows that they were fine to use. Needless to say i wasn't very happy with his comment and still made him switch out for bags that were not swollen. my question is his he right was the shock ok to use or had it gone bad. seems to me that if the bags are swollen that means the chlorine gas had been released and the stuff was just mainly powder. any ideas

1. It's probably not chlorine gas per se, but something worse :eek: , like nitrogen trichloride!

2. In one sense, the shock was probably still 'good', in the sense that it still contained 95% or more of its original chlorine strength.

3. Having opened many containers of old chlorine, I'd personally take back any chlorine material that's off-gassing. It's fine, once it's in the pool, but it's nasty to work with.

4. The "anyone with a basic . . ." claim is nonsense. We have plenty of people here, with advanced degrees in chemistry, that still have to learn about pool chemistry here. Pool chemistry is not normally taught in either basic or advanced science classes!

Sure it's fine to use, but if it's swollen like that, I would be worried about opening it up and getting a snoot full of gas. I've gotten really cautious with any closed up chlorine products, after experiencing some of the gas from opening puck tubs that have been in the shed for a while. Suggest that since it is fine, send it out with their crew(s) that do pool service.