It happened around shortly after 2 p.m. Friday at a home that is under construction on 45th Street in the Borough Park neighborhood.
The New York Police Department says officers found Alex Santizo, of Queens, unconscious and unresponsive when they responded to a 911 call. The 21-year-old was pronounced dead at a local hospital.
Investigators believe Santizo was hit by a piece of debris and then fell down a shaft from the second to the first floor. A report on the website of the city’s buildings department said the debris had fallen from the ceiling.
Police say they are continuing to investigate.
The NY daily News says that the address, 1229 45th St., where the accident happened, has seven open violations and one open complaint with the buildings department.