The cause of so many of the trucks being destroyed is to be said the placement of the trucks being so close to the collapse zone.
At first the firefighters thought they wouldn't collapse and they would be able to save everybody that was trapped. The responding units to the towers that sunny morning were approximately over half of all the units in the New York City Fire Department. There are actually 218 Fire Departments in the New York City fire department and between those departments only 210 of them went to world trade center on 9/11. Most of these departments lost either majority of their men or they were ones that got out early before the towers fell. Some departments lost their rigs (trucks, apparatus) during the collapse of the towers. How many first responders were affected. More than 2,000 NYPD and Port Authority police officers secured the area, searched the Towers, and rescued survivors. They had every officer on duty that day respond the the trade center along with extra people that were either going off duty or just coming on
duty. They even sent in so help from new jersey police officers and PA police officers went also. At least 100 EMS units and dozens of private ambulances raced to the site, setting up triage centers from which to ferry the wounded to hospitals. They sent every ambulance they could find in the city of New York and sent it there because they knew it was worse than 1993 bombing with the van under tower 1.