Hello. I built a subwoofer box to use with my MB Quart RWE202. I have some Handi Fill Fiberglass that I have never used yet and I was wondering, would it be safe to fill the box with this? All it is a fiberglass that is used to fill in blank spaces in walls, ceilings, etc. Anyway, I was curious to see if this would entail any health hazards. If it does, would foam be better? Any help is appreciated. Thanks guys!