Motor blower fixed - covered in insulation material

[Junior1112]

For the past couple of weeks, my motor blower was making a vibrating noise as I turn it up higher and there was no air coming out of the vents. After much difficulty, I was able to remove the motor blower behind the glove box and found that the fan was covered in some kind of fiberglass insulation (see picture). I emptied that out and found lots more of the insulation material blocking a nearby air filter. Once I removed a few more handfuls of this stuff, I put everything back together and the air is flowing again. No more vibrations either. My question is...what exactly is this stuff and how did it get there? Should I be concerned that this stuff is just floating around somewhere under the dash or in the engine?

Thanks!

[alschnertz]

Rodents.