Security was lightened just days before the 9/11 attacks, with the removal of bomb-sniffing dogs from the complex.
The suggestion appears to be that the WTC was running at below normal security levels immediately before the attacks, but we're not sure this is true. Here's the beginning of the Newsday.com story that forms the basis for this claim.
The World Trade Center was destroyed just days after a heightened security alert was lifted at the landmark 110-story towers, security personnel said yesterday.
Daria Coard, 37, a guard at Tower One, said the security detail had been working 12-hour shifts for the past two weeks because of numerous phone threats. But on Thursday, bomb-sniffing dogs were abruptly removed.
"Today was the first day there was not the extra security," Coard said. "We were protecting below. We had the ground covered. We didn't figure they would do it with planes. There is no way anyone could have stopped that."
Note that the story talks of a "heightened security alert" being lifted, and "extra security" being taken away. So the security levels weren't weakened compared to usual, they were just returning to normal levels.
What's more, the idea that all bomb-sniffing dogs were removed appears to be incorrect. Consider this.
Police K9 Sirius... ...was an Explosive Detection Dog with the Port Authority of New York and New Jersey Police Department. Sirius, along with his partner, Police Officer David Lim, were assigned to the World Trade Center in New York, where their primary duty was to check vehicles entering the Complex, clear unattended bags and sweep areas for VIP safety...
On the morning of September 11, 2001, Sirius and Officer Lim were at their Station located in the basement of Tower Two...
Presumably there would have been at least one other dog in tower one, perhaps others working different shifts. It looks like these at least were fixed and not wandering the building, but this would still pose a problem for vehicles bringing explosives. Maybe the WTC wasn't quite so insecure, after all.