Unfamiliar insulation. Could it contain Amosite (aka Cummingtonite/"Brown") Asbestos?

After cutting a plumbing access in an outside wall to inspect some freezing pipes, I discovered an unfamiliar batt-type insulation, consisting of a tar-paper bag filled with loose brown fibers. It doesn't look quite as fluffy as the blown-in cellulose insulation in the attic. Is there any chance that this brown substance could be Amosite asbestos? I know if there's any doubt then you can't tell for sure without testing it, but has anyone worked with this type of insulation before? Is this just cellulose or does it need to be tested? The insulation was most likely installed when the walls were redone. I would like to remove the insulation to replace it with fiberglass in hopes it will help stop the pipes from freezing again.
Incidentally, when the walls were redone they used plaster over some cardboard-like substance stamped "Celotex Lath, This Side to Studs." Anybody familiar with this material? What years did they use such a strange animal? I'd like to figure out what year the fire occurred. Thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sounds like.... Homasote?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
45 years ago they were using wool for insulation. Black outer covering with what you described on the inside. Is this house that old?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Oh yeah it's that old. The house was originally built in 1889. Some of the original lath and plaster walls have horsehair in them. Rough-cut timber, square-cut nails, balloon framing. I'm not good at dating building materials, but after the fire they used mainly drywall and plaster, except in the kitchen they used plaster over the strange Celotex stuff. It comes in 2x4' sheets and looks a lot like homasote board, just from the pictures of homasote that I've seen. From what little I know your approximate dating of 1959 for the insulation seems to jibe with the use of plaster-over-drywall during the transition from lath to drywall. Do you know more about this Celotex lath? Could it also be suspect? Did they ever even use Amosite in residential building materials?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.