[Eric72]

I've noticed something odd with the toploaders I've purchased this year. They appear to have been made with a different "recipe" than what I've gotten in the past. They have a definite chemical aroma. For long-term storage, I personally will not seal these "new recipe" toploaders in an air-tight manner. I simply don't know how the"off-gassing" might react with my cards in a sealed environment.

Just my unscientific opinion. Do your own research.