I just opened a couple of watch batteries that were in blister packs. They are large batteries - the size of nickels. The blister 'popped' when I opened it, certainly it was air-tight. There was a noticeable chemical odour that emanated from it when it was opened. Did this with both batteries. I thought perhaps it was mere offgassing from whatever products were in the battery or the packaging, but I notice that there is no residual odour on the battery or packaging. Seconds after opening, I cannot smell it on them at all. That makes me wonder if perhaps it was whatever gas was in the blister. Is it possible that they might use some sort of gas that wouldn't degrade the battery?