Not sure how that was meant but you were correct in your earlier post. TWA800's center tank was not fueled prior to departure. That tank contained only the residual fuel which remains when a tank is pumped "dry". With a few hundred pounds of fuel in the tank a combustable mixutre would not have occurred.

An additional issue is that it was a hot day at JFK and the airplane's air conditioning packs had been running for some time prior to departure. Those packs are located directly below the center fuel tank so they would have heated the contents of the tank significantly.