Social Security Questions? Ask a Social Security Expert
I am sympathetic to your situation. You asked Where is it written that the 9/11 volunteer benefits are considered workman's comp benefits?
The answer to your question can be found in the following link
PR 02505.035 New York
A. PR 08-029 World Trade Center Volunteer Fund Benefits (WTCVF)
You will see in the opinion that because the law was written and amended under NY worker compensation law the reason is addressed.
Unfortunately this is Effective from 09/17/2015 - Present.
I sincerely ***** ***** could advise differently.