This image, showing the site of WTC 7, is a small portion of a large high-resolution photograph taken by an airplane flying at 3,300 feet on September 23, 2001. It appears that much of the building's remains have already been removed.

The precisely vertical collapse of WTC 7 at 5:20 on the afternoon of September 11th, 2001, necessitated that all of the load-bearing columns be broken at the same moment. Inflicting such damage with the precision required to prevent a building from toppling and damaging adjacent buildings is what the science of controlled demolition is all about. No random events, such as fires or explosions, could be expected to result in such a tidy and complete collapse.

Moreover, it is a fact that fire has never caused any steel frame high-rise building to collapse in any manner, let alone with the vertical precision of Building 7's destruction. ¹

FEMA on Building 7

Despite the inescapable logic of the above, the official theory for the collapse, as published in Chapter 5 of the FEMA report goes as follows:

At 9:59 AM (after the South Tower collapse), electrical power to the substations in WTC 7 was shut off.
Due to a design flaw, generators in WTC 7 started up by themselves.
Debris from the collapsing North Tower breached a fuel oil pipe in a room in the north side of the building. (This means the debris had to travel across WTC 6 and Vesey Street -- a distance of at least 355 feet -- penetrate the outer wall of WTC 6, and smash through about 50 feet of the building, including a concrete masonry wall.)
This, and other debris (that also made the journey across Building 6 and Vesey Street), managed to start numerous fires in the building. (Unfortunately, this event did not prompt anyone to turn off the generators.)
The backup mechanism (that should have shut off the fuel oil pumps when a breach occurred) failed to work, and the fuel oil (diesel) was pumped from the tanks on the ground floor to the fifth floor where it ignited. The pumps emptied the tanks of all 12,000 gallons of fuel.
The extant fires raised the temperature of the spilled fuel oil to the 140 degrees F required for it to ignite.
The sprinkler system malfunctioned and failed to extinguish the fire.
The burning diesel fuel heated trusses to the point where they lost most of their strength, precipitating a total collapse of Building 7.

The last point is the greatest stretch, since it asks us to believe that an event that would be expected only to cause the sagging of a floor instead led not only to total collapse, but to such a tidy collapse that directly adjacent buildings were scarcely even damaged. This is surprising behavior for a steel frame skyscraper designed to survive fires, hurricanes, and earthquakes.

After laying out this highly improbable scenario, the FEMA report authors conclude:

The specifics of the fires in WTC 7 and how they caused the building to collapse remain unknown at this time. Although the total diesel fuel on the premises contained massive potential energy, the best hypothesis has only a low probability of occurrence. Further research, investigation, and analyses are needed to resolve this issue.

Unfortunately for investigators hoping to resolve this issue, nearly all of the evidence had already been destroyed by the time the FEMA report was published.

Documents Destroyed

At the time of its destruction, Building 7 housed documents relating to numerous SEC investigations. The files for approximately three to four thousand cases were destroyed, according to the Los Angeles Times. Among the destroyed documents were ones that may have demonstrated the relationship between Citigroup and the WorldCom bankruptcy. ²

References

1. Burning Diesel Is Cited in Fall of 3rd Tower, New York Times, 3/2/02
2. SEC & EEOC: Attack Delays Investigations, National Law Journal, 9/17/01

page last modified: 2006-01-19