Police say six people were injured, three of them critically, when a building partially collapsed in St. James Thursday.

One of the critically injured victims had to be airlifted to Stony Brook University Hospital.

Suffolk detectives responded to a 911 call that came in at around 1:30 p.m. at 840 Middle Country Road.

The former storage facility was under construction at the time of the collapse. It was set to be transformed into a car dealership.

Workers were up high on a lift taking down the facade of the building when the wall suddenly fell on top of them.

"As they were doing some renovation work, taking it down, the whole front facade of cinder blocks came crumbling down and landed on several individuals," Harrison says.

He says some workers were about two stories up when the wall came down - working on a device called a scissor lift.

John Gomes was part of the construction crew that was working on the building. He says he just heard a noise and then the front of the building came down.

"You didn't see what happened - you just saw the wall fall down on the machines," Gomes says.

Jaime Armendariz, who works at a nearby car wash, rushed in to help the injured workers with a police officer.

"They were already on the ground, and they didn't move, they didn't respond," Armendariz says "I saw the police officer shaken up - I've never seen a police officer like that."

The architect - Mancini Mui, based in Smithtown, did not comment to News 12, but police say they have proper permits in place.

The Occupation Safety and Health Administration were on the scene investigating if any rules were violated.

The exact cause of the collapse is not yet known.

The Smithtown Building Department says it does not have confidence in the integrity of the remaining walls but plans to stabilize it under the supervision of the architect and engineer.