1920s stove pipe walled off behind kitchen
It almost certainly is in sections, but to get the first section out you'll have to get the T away from the wall.

Asbestos putties were really common.  That said you have a choice, pull it out and stay ignorant, or add probably $2000 to the removal cost to have a test and an abatement firm come out.  The asbestos could have been in the clay pipe, but more likely was in a fireseal putty used between sections.