Why Did 7WTC Collapse Again?

As this Village Voice article notes, there are still a lot of questions left unresolved with regard to the events on September 11, 2001. The reason for the collapse of 7WTC is certainly one of the biggies:

Seven World Trade Center—where, besides OEM, the CIA, Salomon Smith Barney, and other entities had offices—was the last building to collapse on 9-11. It was also probably the first steel skyscraper anywhere to collapse solely because of fire. We still don't know why. While NIST has completed its twin towers reports, it has delayed its 7 WTC report twice; it's currently not expected until next spring.

Several 7 WTC tenants, including OEM and the Secret Service, had tanks filled with diesel fuel to power emergency generators. If that fuel leaked and burned, it may have heated the building's steel supports to the point of failure, but according to FEMA's report on the collapse this "best hypothesis has only a low probability of occurrence."

I knew there was a big mystery surrounding the collapse of 7WTC, but I had no idea that the National Institute of Standards and Technology has twice delayed the release of its report on this matter.

Interesting.