If you have ever seen Gilbert Gottfried in the documentary "The Aristocrats", you'll know that jokes like these are par for the course after a disaster.
Part of that documentary showed him on-stage at one of those Comedy Central "Celebrity Roasts" shows. The show was held like, a month after 9-11 occurred, and so everyone was shying away from jokes about death/dying/planes/etc.
Well, Gilbert starts out with a joke about being concerned that his flight was going to take a lay-over at the Empire State Building, and the entire room was completely silent - some people even booed.
So, knowing that he had already reached the pinnacle of distastefulness, he started telling the Aristocrats Joke. Needless to say, that part of the Comedy Central show was never aired.
Clearly the dude has no boundaries when it comes to "tragic" material - and I applaud him for that.