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The rest of the Champlain South tower is being demolished in Surfside, Florida, north of Miami Beach, late on July 4, 2021. Image Credit: AFP

SURFSIDE, Florida: Rescuers were given the all-clear to resume work looking for victims at a collapsed South Florida condo building after demolition crews set off a string of explosives that brought down the last of the building in a plume of dust.

Miami-Dade County Mayor Daniella Levine Cava told the Associated Press that the demolition went “exactly as planned’’ around 10:30pm on Sunday.

Crews immediately began clearing some of the new debris so rescuers could start making their way into parts of the underground garage that is of particular interest. Once there, they were hoping to get a clearer picture of voids that may exist in the rubble and could possibly harbor the 121 people believed to be trapped under the fallen wing of the Champlain Towers South in Surfside that collapsed June 24.

No one has been rescued alive since the first hours after the collapse. On Sunday, Miami-Dade police identified David Epstein, 58, as one of the 24 people known to have perished in the fallen tower. His remains were recovered Friday.

Shortly after the demolition, cranes were again in motion at the site, suggesting that crews were back in place in the wee hours of Monday morning to sift through the rubble from above and below.

Rescuers are hoping the demolition will give them access for the first time to parts of the garage area. Once a new pathway into the initial rubble is secure, “we will go back to the debris pile, and we’ll begin our search and rescue efforts,” Miami-Dade Fire Chief Albert Cominsky said at a press conference several hours before the remaining wing of the residential high rise came tumbling down.

During the demolition, a loud rat-at-tat of explosions echoed from the structure. Then the building began to fall, one floor after another, cascading into an explosion of dust. Plumes billowed into the air, as crowds watched the scene from afar.

“It was picture perfect. Exactly what we were told would happen,’’ Levine Cava said in an interview shortly after the demolition.

Building was unstable

Levine Cava expressed relief that the search for victims can now continue, after being suspended on Saturday so workers could begin rigging the damaged but still-upright portion of the the partly-collapsed tower with explosives _ a precarious operation that could have caused the structure to fail.

“I feel relief because this building was unstable. The building was hampering our search efforts,’’ Levine Cava said.

Some residents had pleaded to return to their homes one last time to retrieve belongings left in haste, but were denied. Others wondered about the pets left behind, even though officials said they found no signs of animals after making three final sweeps, including the use of drones to peer into the abandoned structure.

Approaching Tropical Storm Elsa has added urgency to the demolition plans with forecasts suggesting there could be strong winds in the area by Monday. President Joe Biden declared a state of emergency in Florida because of the storm, making federal aid possible.

The latest forecasts have moved the storm westward, mostly sparing South Florida, but National Hurricane Center meteorologist Robert Molleda said the area could still feel effects.

“We’re expecting primarily tropical storm force gusts,’’ Molleda said, referring to gusts above 64kph.

The decision to demolish the remnants of the Surfside building came after concerns mounted that the damaged structure was at risk of falling, endangering the crews below and preventing them from operating in some areas. Parts of the remaining building shifted on Thursday, prompting a 15-hour suspension in the work.

$935,000 paid for demolition

Authorities had gone door-to-door to advise nearby residents of the timing of the demolition, and to ask them to keep windows closed. They were told to stay inside until two hours after the blast to avoid the dust raised by the implosion.

The method used for Sunday night’s demolition is called “energetic felling,’’ which uses small detonation devices and relies on the force of gravity. Levine Cava, speaking ahead of the demolition, said that should bring the building down in place, containing the collapse to the immediate surroundings so as to minimally disturb the existing mound of debris _ where scores of people are believed to be trapped.

Officials used tarps to visually mark the search area, in case new debris scattered unexpectedly.

State officials said they hired the BG Group, a general contractor based in Delray Beach, Florida, to lead the demolition. They did not immediately respond to an inquiry about how the firm was selected, but a contract for the project calls for the state to pay the company $935,000.

A spokesperson for the state’s Division of Emergency Management said the company subcontracted with Maryland-based Controlled Demolition Inc., which experts say is among only a handful of companies in the US that demolishes structures using explosives. The company was supposed to place explosives on the basement and lobby levels of the still-standing structure, according to the contract for the work.