Fiberglass is through out your house as it is in most houses. Fiberglass is in or around your A/C or heating system. If your have an old system that is externally insolated it is done with standard insolation. If new and externally insolated it is again standard but if internal it is sealed. Most sound tubes and planks are also made with duct board not loose insolation for the most part and is less prone to seperation or flaking. You would have to take the covering off and play in it to bother it enough for it to get it into your lungs and by then your skin would be so itchy you would go out of your mind and your kids would only play with it once trust me.
I myself do not worry about it and I work with it or around it all the time.
I myself do not worry about it and I work with it or around it all the time.