(CNN) – At least four people have been killed and 159 missing after a condo tower collapsed in southern Florida early Thursday morning. Now, as the search for survivors continues, an important question arises: What caused the building to collapse?

At this point, officials promise an emergency investigation because engineers say it is impossible to know an exact cause. Local officials, familiar with the condo complex, which is only four decades old, have repeatedly denied rumors that it is in a state of disrepair.

Kenneth Director, attorney for the building’s condo association, warned against early speculation. The building has been under continuous scrutiny by CNN over the past few months as part of its historic 40-year security certification process.

“Nothing like this is unpredictable,” the director said. “At least the building was not viewed by engineers looking at it from a structural perspective.”

The only repair that has been done recently, he added, It works on the roof.

At a news conference Thursday in Surfside, Florida, Mayor Charles W. Burkett rejected the suggestion that roof repairs should have been a red flag. (It is unclear whether the engineer’s inspection process identified other concerns or suggested any other work.)

“There is no reason for this building to collapse. If someone does not pull the supports out from underneath, or they will sink, or there is a sinkhole or something, it will collapse,” Burkett said. “Work was being done on the roofs, but work was going on all the time on the roofs of the buildings.”

Experts who saw the scenes of the disaster gave a basic understanding of what happened in these scenes, but a little differently.

Call This collapse is a classic column failure. This means that the building itself is supported by a series of pillars. If the pillars fail, everything else fails, “said Kit Miyamoto, a structural engineer and head of the California Seismic Protection Commission.

Determining what caused that failure is a test waiting for federal, state and local engineers.

“This building was exactly what you would expect from a 40-year-old building located in the Atlantic Ocean,” the director said.

But that proximity to the sea, and the salt water leaving the sea, has been a constant problem for experts trying to understand the disaster.

Miyamoto and Greg Batista, both experts in concrete repair projects, oversaw the building’s waterfront location. The potential for chipping, the dangerous failure caused by the oxidation of reinforced steel into concrete, is enormous when a structure such as a building on a surfboard crosses the ocean.

“I’ve seen hundreds of buildings with concrete problems on the beach,” Batista said. “If it is not maintained, whether it is a specific problem or a solution problem, it can be a bridge, it can be a building, it can be a dam or a boardwalk; these kinds of things happen if they are not taken care of.

Thursday, USA Today The first reported case of a study published last year shows that the collapsed building, unlike other buildings around it, collapsed at an approximate rate. 2 millimeters Per year between 1993 and 1999. The research focused on the effects of landslides, gradual subsidence or landslides on the risks of coastal flooding. It does not monitor the condition of the building, so it is not clear whether the structure continued to sink at the rate described in the study.

But Shimon Vodovinsky, co-author of the study and professor of environmental studies at Florida International University, warned that his research did not provide undeniable evidence.

“Other buildings in the eastern part of the city have not been moved,” Wdowinski told CNN. “If it’s a precursor, it’s unique to that building.”

When asked directly whether drowning or drowning could be a factor in the decline, Wdowinski said more information was needed before a verdict could be handed down.

“If everything moves to the same level, not so much”, but “if one part of the building moves relative to another, it can cause some tension and cracks,” he told CNN. “Let’s start some immersion process.”

In an interview on Friday, Kobe Corp., a colleague at the American Architectural Institute, said residents would have recognized the signs if the building’s “solution” was inconsistent.

“People in the building will see cracks in their floors, the table will not be flat and things will fall apart,” Corp said. You will see cracks in the walls. If you look at the ceiling you can see cracks in the ceiling. ‘

It is not clear whether such complaints have been registered with the building management.