Federal investigators at the National Institute of Standards and Technology (NIST) have issued a preliminary report on the cause of the 2021 collapse of a 12-story beachfront condominium that killed 98 people near Miami.
The NIST report, which is not yet definitive but represents the years-long efforts of six investigators, said the Champlain Towers South building likely began to fall when the pool deck slab decoupled from supporting columns about seven minutes prior to the final event. Basically, the pool deck collapsed and dragged the residential tower down with it.
Investigative lead Judith Mitrani-Reiser noted in the report the building was in distress weeks before the collapse as the structure began to deflect due to the shift in applied force as the columns and pool deck came apart. A sliding glass door came off its frame, horizontal cracks appeared in concrete walls, and a gate began shifting vertically, causing it to jam so it could not be opened.
“All of these issues were concentrated in a small area of the pool deck and street-level parking deck, which has been confirmed to have begun collapsing at least seven minutes before the tower,” the report read.
The day before the collapse, water began leaking from the ceiling of the garage below the pool. Over the hours before the collapse, this leak increased into a torrent.
The team used computer simulations, large-scale structural testing and recorded evidence of the building’s distress in the weeks before failure to reach its preliminary conclusion. It is still refining its analysis of the impacts of steel reinforcement corrosion, concrete shrinkage, and improperly built construction joints in the pool deck slab, which all contributed to the collapse.
“The ultimate goal of the NIST investigation is to determine the technical cause of the collapse and, if indicated, to recommend changes to building codes, standards and practices, or other appropriate actions to improve the structural safety of buildings,” said investigative co-lead Glenn Bell.
“There are millions of high-rise condominium units in Florida alone, many of them aging structures near the ocean. While a NIST investigation is intended to identify the cause of the Champlain Towers South collapse, it could also uncover potential issues in other similar buildings nearby and throughout the nation.”
The Champlain Towers South investigation team plans to provide its next detailed public update in Spring 2026.
