That's just the number on wikipedia. 430,000 people lost their jobs in the 3 months after the attack. I supposed you could argue that it's not direct damages in the sense that 430K people were not all office workers in the WTC, but if they lost their job within 3 months of the attack it seems like the job loss is pretty directly related.

And, as a former NYC resident I would not at all be surprised if 430K people really did directly lose their job. The sheer number of people working in that area is immense. I remember an interview at the time with a guy whose bodega located down by Wall Street was destroyed, and he said he did $80K per week in business. And that's just one dude selling sodas, bottled water, cigarettes, etc.