On Dec 19, 4:37 pm, wrote:
I noticed a nice cool breeze in the basement.
Turns out that it's one of those old homes with
no insulation in the walls, where it's open in places
all the way from the attic to the basement. Someone
back in the distant past appears to have stuffed
doubled over carpet in the basement ceiling
at the wall.

What should I use to do the seal properly, and
get rid of the decaying carpet. I considered spray
foam, and some books I looked at recommended
stuffing fiberglass in the hole, but I am leary of using
fiberglass in areas I might be wandering around in.

Any ideas?

I have the idea that you won't live forever and that fiberglass
insulation stuffed up into a wall cavity in a basement won't affect
your health or longevity. Expanding foam will work, but it will cost
way more and it is probably worse for your health than the fiberglass.

R