One man is dead and another is critically injured after a nine foot retaining wall collapsed on them while doing construction work at a home in Brooklyn.  

The FDNY responded to a call about a collapsed wall just after 1 P.M. Monday at a building on 42nd Street near 5th Avenue in Sunset Park.

Fire officials say the two men were working on an adjoining property on 43rd Street.

Owners of the 42nd Street building allowed them to do work near the property line.

Fire officials say when they arrived at the scene to assist, one man was already dead and the other was taken to the hospital with critical injuries. 

"Our units went in and removed the debris from the two workers that were in the collapse,” said J.J. Boylan, FDNY deputy chief. “Then after we had removed them, to ensure there were no other victims, NYPD went in and with their k9 unit to do a sweep to ensure all victims were accounted for."

A third worker on the job had left to grab lunch, and when he returned he saw the wall had collapsed, officials say.

Department of Buildings (DOB) inspectors found that the workers were hired by the owners of 453 43rd Street to perform masonry repair work on the retaining wall and were granted access to the adjoining backyard of 454 42nd Street as part of the ongoing work.

There were no DOB permits issued for any construction work at either property.

The workers were excavating the length of the retaining wall without adequate shoring, resulting in the wall's collapse at 454 42nd Street, officials said.

A partial vacate order has been issued for the backyards of both 454 42nd Street and 453 43rd Street.

The Department of Buildings investigation is ongoing.