A partial collapse of a parking garage under construction at the Children’s Hospital of Philadelphia on Thursday resulted in one confirmed fatality and left two workers missing, who are presumed dead. The incident occurred when a roof segment gave way, causing the entire seven-floor stairwell to fall in succession.

Video footage showed the stairwell collapsing rapidly, trapping several construction workers beneath the debris. Emergency responders were able to rescue one individual, who was quickly transported to a local hospital but later succumbed to injuries, according to city officials.

The two other workers involved have not been found and are believed to have died in the collapse. Authorities continue search and recovery efforts at the site while investigating the cause of the structural failure.

The Children’s Hospital of Philadelphia and local officials have not yet released additional details regarding the identities of the victims or the timeline for resuming construction activities. The incident has raised concerns about safety protocols on the project, which was still underway at the time of the collapse.