The Champlain Towers, a condo based in Southern Florida which collapsed on Thursday, has been an at-risk structure for decades, according to a researcher and professor of the Florida International University.

Shimon Wdowinski, who works in the university’s Institute of Environment said that the building had shown signs of sinking since the 1990s, according to a study he conducted last year, reported CNN.

Even though Wdowninski suggested that the sinking of the building could be a contributing factor to its downfall but is unlikely to have caused the incident.

He said, “If one part of the building moves with respect to the other, that could cause some tension and cracks”, reported CNN.

Between 1993-1999, the Champlain Towers carried a subsidence rate of approximately two centimeters per year, Wdowninski’s study found.

“We noticed that the building was moving, and we reported that in the study, but we’ve seen buildings in other areas… moving at even higher rates, so we didn’t think it was something unusual. What’s unusual is that today it collapsed”, he said while discussing Thursday’s collapse that has already claimed one life.

According to Wdowninski, the sinking was noticed in the surrounding areas of the Champlain Towers South, however, larger areas of western Miami Beach had similar subsidence.

According to the recent updates, at least 99 people remain unaccounted for after the incident. However, rescue and mitigative operations are underway at the site.