(SURFSIDE, Fla.) — At least 12 people are dead and 149 others remain unaccounted for after a 12-story residential building partially collapsed in South Florida’s Miami-Dade County last week, officials said.

A massive search and rescue operation entered its seventh day on Wednesday, as crews continued to carefully comb through the pancaked pile of debris in hopes of finding survivors. The partial collapse occurred at around 1:15 a.m. local time last Thursday at the Champlain Towers South condominium in the small, beachside town of Surfside, about 6 miles north of Miami Beach. Approximately 55 of the oceanfront complex’s 136 units were destroyed, according to Miami-Dade Fire Rescue Assistant Chief Raide Jadallah.

So far, 125 people who were living or staying in the condominium at the time of the disaster have been accounted for and are safe, according to Miami-Dade County Mayor Daniella Levine Cava, who stressed that the numbers are “very fluid” and “continue to change.” Officials were previously including the number of deceased among those accounted for but are now separating the figures.

“We are continuing to make headway in our search,” Levine Cava said during a press conference in Surfside on Tuesday evening.

‘Nobody is giving up hope here’

The remaining structure that still stands was cleared by rescue crews last week and all resources have since shifted focus to the debris, according to Jadallah. Hundreds of first responders and volunteers have been working around the clock to locate any survivors or human remains in the wreckage. However, heavy rain and lightning storms have periodically forced them to pause their efforts.

Surfside Mayor Charles Burkett acknowledged that there have been questions about how long someone could survive beneath rubble, telling reporters: “There didn’t seem to be a good answer to that.” But he insisted that search and rescue efforts are continuing unabated.

“Nobody is giving up hope here. Nobody is stopping,” Burkett said during a press conference in Surfside on Tuesday afternoon. “We are dedicated to getting everyone out of that pile of rubble.”

Crews have cut a vast trench through the pile to help enhance their search, according to Levine Cava. As of Tuesday afternoon, they had moved more than 3 million pounds of concrete, which equates to over 850 cubic feet, according to Miami-Dade Fire Rescue Chief Alan Cominsky.

Meanwhile, dump trucks have begun moving debris to an alternate site, according to Kevin Guthrie, director of the Florida Division of Emergency Management, who told reporters that rescuers have “all the resources” they need.

Crews have still not physically reached the bottom of the pile but cameras placed inside showed voids and air pockets where people could be trapped, according to Jadallah.

More than 80 rescuers — each working 12-hour shifts — are on the pile at a time, listening for sounds and trying to tunnel through the wreckage, according to Andy Alvarez, the Miami-Dade Fire Rescue’s deputy incident commander overseeing search and rescue efforts. Alvarez described the process as both “frantic” and painstaking.

The conditions on the pile are “bad” and “not ideal” for rescuers, Alvarez told ABC News, due to heat, humidity and rain. But search and rescue efforts are still continuing 24 hours a day. Crews are using various equipment and technology, including underground sonar systems that can detect victims and crane trucks that can remove huge slabs of concrete from the pile, Alvarez said.

The site has also proven to be dangerous for rescuers. One area had to be roped off Tuesday due to falling debris, according to Burkett, and crews are no longer entering the remaining structure because it is considered unstable, Levine Cava told reporters.

Some of the first responders are members of the Miami-Dade Fire Rescue’s urban search and rescue team, Florida Task Force-1, which is part of the Federal Emergency Management Agency’s National Urban Search and Rescue Response System and has been deployed to disasters across the country and around the world. Search and rescue teams from Israel and Mexico have also joined the efforts in Surfside.

Although officials have continued to express hope that more people will be found alive, no survivors have been discovered in the rubble of the building since the morning it partially collapsed. Bodies, however, have been uncovered throughout the site, which crews have categorized into grids, according to Cominsky. The fire chief told reporters that rescuers with specially trained dogs are still “constantly” “searching for life” amid the debris.

Officials have asked families of the missing to provide DNA samples and unique characteristics of their loved ones, such as tattoos and scars, to help identify those found in the wreckage.

President Joe Biden and first lady Jill Biden will travel to Surfside on Thursday, according to a statement from the White House. Last week, the president approved an emergency declaration in Florida and ordered federal assistance to supplement state and local response efforts in the wake of the partial building collapse.

Investigation ‘will take a long time’

The cause of the partial collapse to a building that has withstood decades of hurricanes remains unknown. The Miami-Dade Police Department is leading an investigation into the incident.

Levine Cava told ABC News last Friday that there was no evidence of foul play so far but that “nothing’s ruled out.”

Built in the 1980s, the Champlain Towers South was up for its 40-year recertification and had been undergoing roof work, according to Surfside officials.

The partial collapse happened as the Champlain Towers South Condo Association was preparing to start a new construction project to make updates, according to Kenneth Direktor, a lawyer for the association. Direktor told ABC News that the building had been through extensive inspections and the construction plans had already been submitted to the town but the only work that had begun was on the roof.

Direktor noted that he hadn’t been warned of any structural issues with the building or about the land it was built on. He said there was water damage to the complex, but that is common for oceanfront properties and wouldn’t have caused the partial collapse.

A structural field survey report from October 2018, which was among hundreds of pages of public documents released by the town late Sunday, said the waterproofing below the condominium’s pool deck and entrance drive was failing and causing “major structural damage to the concrete structural slab below these areas.” The New York Times was first to report the news.

In a November 2018 email, also released by the town, a Surfside building official, Ross Prieto, told the then-town manager that he had met with the Champlain Towers South residents and “it went very well.”

“The response was very positive from everyone in the room,” Prieto wrote in the email. “All main concerns over their forty year recertification process were addressed. This particular building is not due to begin their forty year until 2021 but they have decided to start the process early which I wholeheartedly endorse and wish that this trend would catch on with other properties.”

A former resident, Susanna Alvarez, told ABC News that Prieto said during the 2018 meeting that the condominium was “not in bad shape” — a sentiment that appears to conflict with the structural field survey report penned five weeks earlier.

ABC News obtained a copy of the minutes from the November 2018 meeting of the Champlain Towers South Condo Association, which stated that Prieto had reviewed the structural field survey report and “it appears the building is in very good shape.”

Prieto has not responded to ABC News’ repeated requests for comment. He is no longer employed by the town of Surfside. He has been placed on a “leave of absence” from his current post as a building inspector in nearby Doral, according to a statement from the city on Tuesday.

When asked on Monday whether Prieto misled residents during the 2018 meeting, Burkett told ABC News: “We’re going to have to find out.”

A 2020 study conducted by Shimon Wdowinski, a professor at Florida International University’s Institute of Environment in Miami, found signs of land subsidence from 1993 to 1999 in the area where the Champlain Towers South condominium is located. But subsidence, or the gradual sinking of land, likely would not on its own cause a building to collapse, according to Wdowinski, who analyzed space-based radar data.

Miami-Dade County officials are aware of the study and are “looking into” it, Levine Cava told ABC News last Friday.

Miami-Dade State Attorney Katherine Fernandez Rundle said she plans “to request that our Grand Jury look at what steps we can take to safeguard our residents without jeopardizing any scientific, public safety, or potential criminal investigations.”

“I know from personally speaking with engineers from the National Institute of Standards and Technology that their investigation to determine exactly how and why the building collapsed will take a long time,” Rundle said in a statement Tuesday. “However, this is a matter of extreme public importance, and as the State Attorney elected to keep this community safe, I will not wait.”

Lawsuits against the Champlain Towers South Condo Association have already been filed on behalf of residents, alleging the partial collapse could have been avoided and that the association knew or should have known about the structural damage.

A spokesperson for the Champlain Towers South Condo Association said they cannot comment on pending litigation but that their “focus remains on caring for our friends and neighbors during this difficult time.”

“We continue to work with city, state, and local officials in their search and recovery efforts, and to understand the causes of this tragedy,” the spokesperson told ABC News in a statement Monday. “Our profound thanks go out to all of emergency rescue personnel — professionals and volunteers alike — for their tireless efforts.”

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