Miami building collapse - updates: Death toll reaches 12 as extra rescue team requested amid tropical forecast

Forensic engineers will have to investigate the building’s ground-floor columns, according to Sinisa Kolar, a Miami-based engineering executive.

“The key element to this investigation, in my opinion, lies in that rubble, in those columns and condition of the structural elements,” said Mr Kolar.

He told CNN that investigators will have to test samples of concrete and examine its condition, and cross-reference it with the structural drawings of the building.

Surfside’s mayor Charles Burkett says that initial tests show that the town’s air is not toxic, following the 12-storey condo collapse.

Mr Burkett told CNBC’s Shepard Smith that he felt positive about the air quality after meeting with an engineer and specialist.

“I came away feeling very good about breathing in all of that smoke and stuff that you and I were breathing in all day that day, because that was the worst day,” Mr Burkett said on Monday evening.

“I still have a little chest pain from inhaling all that smoke.”

The US State Department is speeding up the visa process for relatives of residents of the collapsed condo building, according to the office of Senator Rick Scott.

There are at least 36 people from Latin America, including Argentina, Chile, Colombia, Cuba, Paraguay, Uruguay and Venezuela, among the missing.

“We are working directly with the State Department to ensure quick processing of visa applications,” Mr Scott’s communications director McKinley Lewis told the Miami Herald.

“Senator Scott’s office has already helped several families expedite their travel and is very appreciative of the responsiveness State has shown in helping those affected by this terrible tragedy.”

Robert Lisman, a resident of a sister building to Champlain Towers South, told NBC Miami a crack in his block was caused by “concussion” from the collapse of the beachfront condo on Thursday.

He told the network that Miami that he had concerns but believed there was “no imminent threat” of collapse.

“I have concerns but I am not panicking,” Mr Lisman said. “I know there are things we need to address and look at, but there is no imminent threat. I’m confident in my building, Champlain Towers East”.

It comes as officials survey the Champlain Towers East and North, another sister building constructed a year after Champlain Towers South. Residents were offered to evacuate from the blocks.

Owners of apartments in Champlain Towers South were days away from repairs that were due to cost $15 million (£10.8 million), according to documents obtained by CNN.

As part of a 40-year recertification process, the Champlain Towers South condo association approved the repairs in April. Two years after the association’s members were informed of "major structural damage".

Apartment owners were due to pay $80,000 (£58,000) to $336,000 (£260,000) for the repairs, depending on the number of rooms. Owners could pay upfront, or decide on a monthly fee for a 15 year period.

It is unclear if the issues identified in a 2018 report were the cause of the tragedy, which structural engineers have suggested was the result of a “failure” at the foundation of the 1981 structure.

Officials are also coming under fire for telling a 2018 meeting of the condo association that the building was in good shape following the damning report.

Residents of a sister building, Champlain Towers North, have decided to stay in their apartments despite the offer of evacuation.

The block, which was constructed a year after the fallen Champlain Towers South, has faced the same salty air, annual storms, and threats of rising sea levels that some structural engineers have suggested contributed to the tragedy on Friday, in which 150 are missing and 11 dead.

Philip Zyne, who lives with his wife on the fifth-floor of the sister building, told the Associated Press: "I've never seen any major structural issues. I'm not worried at all right now.”

He added: “I do want to get a full structural engineering and forensic examination done."

An inspection carried out at Champlain Towers North in recent days has found no threat from imminent collapse, with a further investigation due.

The association for Champlain Towers South has faced criticism following the tragedy on Thursday, after the town of Surfside released a number of documents in connection to the building, and a 2018 report that warned of “major structural damage”.

Minutes from a meeting obtained by CNN show that town officials told the residents association in November 2018 that the building was “in very good shape", despite a structural report that was "not in the format for the 40 year certification” required for approval.

That certification process remained incomplete when Champlain Towers South collapsed on Friday, according to reports, with repairs costing $15 million due to begin after approval from the resident’s association in April.

It remains unclear as to why town officials appeared to ignore the report’s warnings of “major structural damage” in that November 2018 meeting, and why it allegedly misinformed the residents association, which is also facing criticism for a years-long delay to carrying out the recertification and repair work.

Officials in Miami-Dade are conducting an audit of all buildings in the county to assess whether or not owners are complying with a requirement for structural integrity at 40 years.

Mayor Daniella Levine Cava said she wants any issues raised by inspections to be immediately addressed within 30 days, following the collapse of Champlain Towers South, which was due to be recertified.

Ms Cava has also urged municipalities within the county to follow suit, with Miami launching a 45-day audit of buildings higher than six stories and 40 years old or older.

“I have concerns but I am not panicking,” said Richard Lisman of a crack that has recently appeared in his block, and a sister building to Champlain Towers South.

“I know there are things we need to address and look at, but there is no imminent threat. I’m confident in my building, Champlain Towers East.”

He told NBC Miami the crack was caused by “concussion” from the collapse of the sister building on Friday, and that he was reassured by an initial assessment carried out by a structural engineer.

Owners of apartments inside Champlain Towers South were informed by the condo association in April that the building desperately needed repair work, as it set out costs of $15 million for the whole building to be repaired.

Jean Wodnicki, the condo association president, warned owners that the concrete damage to the building would “multiply exponentially over the years” and said “the observable damage, such as in the garage, has gotten significantly worse”.

A contractor who visited the condo ahead of the repairs, according to the Miami Herald, was alarmed by cracked concrete around the pool area and water in the basement. It remains unclear if this contributed to the collapse of the building.