The worker, a 43-year-old man, lay trapped after the roof failure, unconscious, following the installation of a new refrigeration unit inside an addition to the original building, city officials said. 

In a statement, Fire Department officials stated emergency responders arrived on the scene within four minutes and found the man trapped beneath a heavy slab of concrete. 

Firefighters used the “jaws of life” and specialized airbags to lift the slab and a piece of heavy equipment, the FDNY said.

The man, whose name was not released pending notification of his family, was taken to Brookdale University Medical Center in critical condition, where he later died, police said. 

The structural failure happened in a concrete extension behind the building, which had been used for storage, according to the Buildings Department, which is investigating the incident.

Workers had been demolishing a walk-in freezer and commercial kitchen, the department said, confirming that no permits for work had been filed with the city. The Brooklyn Paper reported that utility service to the building was shut off after the collapse. 

The Building Department issued a red-tag stop-work order, and multiple investigations have been launched by the City Fire Department, the Department of Buildings, the Office of Emergency Management, and OSHA, police confirmed.