How rescue specialists search for survivors in collapsed buildings

In disasters like Miami, urban search and rescue experts employ resources such as cameras, microphones, and dogs as they work on the pile.

In the early hours of Thursday, June 24, a huge portion of a 13-story building in Surfside, Florida suddenly collapsed. So far, 11 people are confirmed dead from the disaster, and approximately 150 are still missing. Rescue crews are still working to locate survivors and remains in the massive pile of rubble. 

These responders have a challenging and dangerous job. Here’s how the process of digging and searching through rubble works, whether emergency personnel are dealing with a building that has collapsed because of an earthquake, structural failure, hurricane, or act of terrorism. 

The procedure: Searching for a ‘survivable void space’

A five-part procedure guides the rescue specialists who descend on a disaster for however long the process takes. The first step is straightforward information gathering: It’s “response, arrival, and recon,” says Larry Collins, deputy chief of Cal OES Fire & Rescue who has worked on disasters including the 2010 Haiti earthquake. That’s when the responders will try to determine the basics of what they’re dealing with, such as the cause of the collapse (was there an earthquake? a hurricane? something else?) the scope of it, and further details. In Florida, attention is focused on known, preexisting deterioration and damage of the concrete at its base.  

The second stage is “surface rescue,” he says. That’s when personnel will tend to any obvious victims. “It’s the people that are lightly trapped, or trapped near the surface, that you can hear or see,” he says. 

The third part is the “void space search,” he explains. These surviving victims, if they exist, are hidden, and rescue personnel must detect them and get to them carefully. This period of time involves “cutting, breaching, crawling into the voids, looking for people in a survivable void space,” he says. 

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That concept—a survivable void space—is crucial, he says: it’s a part of the collapsed structure where a person could endure for long enough to be rescued. In some disasters, like earthquakes, people have survived in those spaces for multiple days.

The fourth part is “selective debris removal,” he says. Heavy equipment, like cranes, will carefully take the structure apart. Rescue workers at Surfside are “dissecting that building, piece by piece,” he says. Crucially, before lifting off a huge slab, the experts will peer under the material using cameras to ensure no one is under it who could be hurt by the movement. “They want to make damn sure that there’s no one underneath that,” he says. The pace, he says, will be “methodical,” but as quickly as possible given safety constraints.  

The final stage is “when you’ve exhausted every possibility of a live save,” he says. It involves “general debris removal.” All the collapsed material and everything else will be cleared away. Weeks have gone by; the site is totally cleaned up, and any human remains have ideally been recovered. 

How rescue specialists search for survivors in collapsed buildings
Dogs are a crucial way to locate survivors, or human remains. Here, a training exercise in California in 2019. CalOES

The gear: Pry, look, listen, and search with canines 

An urban search and rescue team may travel with some 60,000 pounds of tools and equipment, says Todd Livingston, a retired program manager and leader of search and rescue Task Force 3 in Florida. At the most basic, the gear can include items like a sledgehammer, pry bar, and steel pipe. In a small area, he explains, using a pry bar to leverage a heavy piece of material onto sections of rolling steel pipe can be a way to move it to a more open area. Then, mechanized equipment can pick it up and move it off the pile. 

In other words, the job is physical. Indeed, The New York Times reported that some personnel in Florida have been working at times “with their hands.”  

Generally, rescue teams will do something called “delayering,” which involves removing material from the top of the pile and working downwards, although responders could also work their way in from the side or bottom. 

Livingston says that a team could bore a hole through concrete with a core drill, and then snake a camera through that passage. For example, the SearchCam 3000 not only reveals images to rescue workers, but also has a two-way communication system so that rescuers could talk to a survivor. A camera can also help a team know if it’s structurally safe to use heavy equipment to remove material. “They’re also observing what’s on the other side, so if they do make a breach, that breach is not going to cause a secondary collapse,” he says. 

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Another tech tool at their disposal are microphones. “What a search specialist would do is go out onto the pile, they would call for a quick quiet, and they’d put the microphones out in a pattern,” says Scott Chappell, a board member with the State Urban Search and Rescue Alliance. The mics might have magnets attached to them, so they can be stuck easily onto metal debris. That microphone array could pick up sounds of survivors—an important clue—or just the natural noises of the pile. 

Finally, there are the invaluable canines. “These dogs are unbelievable,” Chappell says. “They get on a pile, and they can smell the folks that are working the pile,” he says. Imagine that there are 10 people working there, he says. “They’ll quickly smell all of the folks that are working, and if there’s a scent that is not related to one of those 10, they hit.” In other words, the dog can ignore the scents it has just learned and focus on any new smells. 

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In addition to hunting for “live finds,” the canines are also trained to find human remains. Eventually, in a disaster, an operation switches from a rescue—looking for survivors—to a recovery, when experts decide there is no longer a chance of finding someone alive. “At some point, events sadly turn toward recovery mode,” he says. When that happens, rescuers will start being more cautious about their own safety. “If we are in a response stance, and we’re still trying to rescue people, we are willing to risk a little more on the rescuer side, and put folks in harm’s way,” he says. 

“While finding all of the missing is very, very important, risking rescuers’ lives for human remains should be balanced,” he adds. The calculus of risk versus reward changes at the sad end of a disaster. 

But in Florida, the search continues, six days since the building first collapsed. 

Editor’s note: This story has been updated to correct an error in the first sentence regarding the date of the building’s collapse.

Rob Verger

Rob Vergeris the Technology Editor at Popular Science. He covers aviation, the military, transportation, security, and other complex tech topics. A graduate of Columbia Journalism School, he's also written for The Boston Globe, Newsweek, The Daily Beast, CJR, VICE News, and other publications. Contact the author here.