The scope of rescue operations at the World Trade Center (WTC) was the most comprehensive of any that occurred in this country. The WTC incident was unique in that this was the first time ever that a steel-frame high-rise building had collapsed—anywhere in the world. Previous structure collapses, such as in the Oklahoma City Bombing, involved steel-reinforced concrete structures and hundreds of collapses of ordinary constructed buildings (brick-and-joist). No wooden shores, which had been used successfully at other building collapses, were used at the WTC because the debris consisted of heavy steel beams and pulverized concrete floors and furnishings. “Shoring” at the WTC consisted primarily of welding together large, unstable I-beams.

The collapses of the towers presented unique problems, both obvious and unexpected. Some of the obvious challenges were the mass destruction, the number and intensity of the fires, and the gigantic size of the structural members. Much of the lightweight concrete and Q-decking were completely pulverized.

One of the most significant unexpected but immediately realized obstacles was the inaccessibility of the main areas that needed to be searched—the center of both towers. Many voids could not be searched at first because of the fires and high-heat conditions. These voids were searched later after conditions improved. Firefighters were operating hoselines around the clock in an effort to suppress the fires. Several times, flames drove us off the top of the debris piles of both towers.

Search operations in the voids. (Photo 1 by FDNY Photo Unit; other photos courtesy of FEMA.)

Another problem was the massive amount of water that had entered the bathtub area. It took a couple of weeks before water was drained out of the lower levels of both towers, which had been flooded, hindering the search on the lower floors.

Weather was not a negative factor in this operation. There were a few showers and a couple of cold nights, but we did not experience the delays we had anticipated during the winter months. The winter was far more moderate than usual; there was no significant snowfall.


At daily meetings with the FDNY command staff, short- and long-term objectives were established. FDNY held briefings twice daily. Acting in the capacity of technical advisor to the command staff, one of my duties was to relay to the contractors daily objectives. The contractors and I developed the daily work assignments based on these objectives.

Rescuers’ safety was always a major priority, even more so when we were not working against time, as we were in the early days of the operation when expectations were that we would find more survivors. In the early days, there were also severe problems with site security. Civilians and untrained and inexperienced personnel who had never operated at a building collapse, although they had good intentions, presented safety concerns and slowed operations.

The site was organized according to the four command sectors, which were then divided into search areas. Each sector had a staff chief, a deputy chief, several battalion chiefs as supervisors, and at least one safety officer.


The most immediate objective was to search every accessible void in the hope of rescuing any trapped survivors. We believed at the time that if we could dig down through the stairwells in both towers, and eventually to the mezzanine and concourse levels, we would be able to reach trapped victims. It was thought that since most of the occupants were evacuating at the time of the collapses, the occupants would most likely be in these areas. Initially, the number of anticipated victims was around 4,000. As time went on, however, this figure was progressively lowered.

We began searching the entire area immediately after the towers fell. Our search efforts were hindered from the start. Smoke and dust blanketed the site for months. The fires in the ruins of both towers continued into the spring. Nevertheless, we searched every area that could be accessed.

We reached the stairwell areas of both towers within 48 hours. It took months to reach the concourse and mezzanine levels, because they had collapsed into the structures’ subterranean areas. These floors ended up as much as 60 feet below street level.

In some cases, we were able to identify our location by the type of construction material that was around us. In a few cases, the bodies were so badly pinned, it took many hours to remove them.


After several weeks, we realized that chances for finding survivors were virtually nonexistent. We changed our tactics to exclude dangerous void entries unless the chief in charge deemed it absolutely necessary. Entry into the voids was done only with the crew’s recommendation and the sector commander’s permission—after the void had been sized up and its stability and safety verified.

After the fires were extinguished and visible victims were removed, a systematic search of the remaining voids was initiated. This was the most dangerous part of the operation.

There were predominantly two types of voids at the WTC: many small pocket voids and large areas voids such as the parking level areas.

The void search (rescue) teams, typically consisting of one officer and five firefighters, included members of the FDNY rescue squads and ladder companies and the FEMA USAR teams. The void team officer, as is standard procedure, was in charge of the team and responsible for safety. His main position was at the void’s entrance.

Searching voids is normally dangerous and unpredictable, but it was even more so at the WTC. The tremendous amount of steel and precarious positions of thousands of tons of heavy debris increased the hazards for searchers: 30- and 50-ton beams were holding up tremendous amounts of debris.

We followed a team concept; each firefighter had a specific assignment and area of responsibility.

Team members wore full personal protective equipment when required. The search teams continuously monitored the atmosphere in which they were searching.

When looking for voids, rescuers removed natural props and supports only when absolutely necessary and when, in the judgment of the experienced crew members, including the officer, it was considered safe to do so. Initially, beams supporting other debris and sections of floors, doors, stairs, and so on were left in place whenever possible. The natural bracing that developed from the collapse was used to facilitate the void search efforts. Generally, the shoring of structural members is preferred over removing them, since removal significantly diminishes the margin of safety under which void firefighters operate. The more debris handled, the slower the search operation.

In accordance with guidelines taught to all FDNY rescue and squad personnel, the officer evaluated each step of the collapse void exploration and determined whether tactics needed adjusting based on a wide variety of scene factors. The officer, responsible for team members’ safety, positioned himself so that he could closely supervise the void entry team and yet be able to monitor the actions of the support team. The officer was in constant communication with team members, particularly those operating in the void, and provided status reports to the operations chief, the incident commander, or his immediate supervisor.

At the WTC, one of the factors that had to be monitored constantly was the movement of heavy equipment in the area. Several times, the equipment had to be shut off and searchers had to evacuate because vibrations were causing shifts in debris, precipitating fears of secondary collapses.

The officer, in conjunction with the sector commander, selected the routes searchers would use to enter the voids and the tactics/procedures to be used. These decisions were based on the initial and continual size-ups. If a major concern surfaced, engineers, rescue team managers, and chiefs were brought in.

Because of extenuating circumstances, including the delay in the arrival of crews because of the closing down of the nation’s air traffic and the shortage of personnel resulting from the decimation of FDNY’s first responders to the WTC, search crews could not be rotated at an optimal pace. The intervals varied. Initially, the crews worked 24-hour shifts; they were given breaks when possible. After the arrival of more experienced and trained rescue crews, we switched over to 12-hour shifts.


Members of the Federal Emergency Management Agency (FEMA) USAR teams and the FDNY Special Operations Command (SOC) served as rapid intervention teams. At least one six-member team was established for each of the four sectors. The teams were fully equipped, ready to intervene immediately and were rotated on a regular basis.


Initially, we used battery-operated reciprocating saws and rebar cutters extensively. The portability of battery-operated equipment helped us set up operations quickly. We had limited access to both towers in the early days. Initially, the only way we could access the tops of both towers was by crane. The cranes brought generators for electrical tools up to our search positions on top of the pile within a couple of days.

It would be helpful in situations like this if technology would permit power units to be made smaller; that would make them more portable and easier to use.


As in all operations, the officer, who is continuously monitoring the changes in the operation, and the commanding officers must be in constant communication, to ensure worker safety. At the WTC, there were major communications problems initially, especially during the first 24 hours. Communications began to improve after FDNY took control of the site.

Another facet of communications is the evacuation signaling system. All personnel must know what the system is and must be able to hear the signals when sounded. After control of the WTC site was secured, the following evacuation communication system, used by FEMA’s USAR teams, was implemented. The signals are sounded by an air horn or some other appropriate device:

  • Evacuate the area: 3 short blasts about one second each.
  • Stop operations; have all quiet: 1 long blast, three seconds in duration.
  • Resume operations: 1 long and l short blast.

The FEMA area marking system was also used at the WTC. Areas were marked with a diagonal line about two feet long (spray painted in orange or red for visibility) to indicate areas in the process of being searched. Areas for which searches had been completed were marked with an “X” (a diagonal line was added to the first line to complete the “X”). Included in the “markings” were the identity of the team that searched the area; the month, day, and time the search was done; and any hazards in that area (the presence of utility pipes and flooding conditions, for example).

The WTC search and recovery operation was the first of its kind in many ways, yet the standard procedures and guidelines we used in the WTC search collapse rescue operation worked once the site was controlled and we were assured that the ongoing fires, flooding, smoke, and the like would not endanger any more of our personnel. Unfortunately, it’s difficult to use the word “success” when so many people were never found.

JOHN P. O’CONNELL, a 23-year veteran of the Fire Department of New York, has been assigned to the department’s collapse rescue, Rescue Co. 3, for 15 years. He is the lead collapse instructor for the city of New York as well as a lead instructor for the state of New York and the FEMA USAR Rescue Specialist Training Program. He is also a member of the FEMA Incident Support Team and a task force leader for the USAR NYTF-1 team. He has instructed throughout the country and abroad. He is a member of the Fire Engineering and FDIC advisory boards. He served as technical advisor to the incident command staff at the WTC.

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