Thanks, Tom! That puts my mind at ease a bit.

The real issue I have is a shelf that is on the other side of that wall
that was put up by he builder when the house was built. My Dad had used
the shelf to store automobile type items for years. One of the items was
a gallon of distilled water that had sprung a leak. Most of the gallon
of water leaked out onto the shelf. I was cleaning the shelf yesterday
when I noticed a 4" x 4" spot of the shelf that looked "hairy" or kind
of "furry" I touched it and it felt like kind of a cloth texture to it.
I took the vacuum cleaner to it and was surprised to see that the furry
material was really the shelving material that had broken down due to
the water bottle leaking on it. After vacuuming the hairy stuff off, I
can see that the shelf is made of some type of compressed shiny fiber
material that I've never seen before. I wondered if maybe the builder of
this house had a plank of asbestos fiber board left over from building
the firewall and decided to put it to use as a shelf on the other side.

I'm so curious as to what kind of material this shelf could be made of??
It's definitely not wood, and it's definitely not a pressed wood board
like they sell at Home Depot strores. Any ideas?
Perhaps it was MDF, which I think stands for Medium Density Fiberboard. It
looks like it is composed of compressed cardboard rather than wood chips and
is usually brown or tan.
Tom.