There is an error in the  lyrics I posted above.  The last line of the 4th verse should read:  [boldface added]

             G                   Em                      C                             D
 Thank God we made it to the street; we ran through ash and smoke.
    G                         Em                   D
 I didn't know which way to run; I thought that I would choke.
      C                     G                       C                   D
 A fireman took me by the arm and pointed me uptown,
             C                           Em                  G                            D
 Then "Christ!" I heard him whisper, as the tower came roaring  down.

The line has been widely misprinted on the web as "...as the tower came pounding down."  I believe that error is even at Paxton's own website.
But if you listen to his free MP3 of the song, he is clearly not saying "pounding."  Initially I thought it sounded like "rolling," though that didn't seem like the best word.  Re-listening, I heard it as "...roaring."

I just looked up the song in my "Sing Out" magazine issue that was published not long after 9-11-01, and the line is printed there as "...roaring," just as it sounds on Tom's MP3.

Genie