It happened just before 12:30 p.m. in an alley near 45th and Moravian streets.
The lift tipped onto its side and fell onto a van, splitting the vehicle in half.
Three people were thrown to the ground from upwards of 30 feet.
Tareek Wilson was just feet away and heard the collapse.
"I turned the corner, it happened so fast. The crane came down and then once the dust settled I noticed there were bodies there," Wilson said.
He ran over as soon as he realized three people were on the ground.
"The workers there that were with them, they tried to move the bodies. I told them not to move them for obvious reasons," he said. "One of the workers was responsive, the other two really weren't moving as much."
Police, L&I and OSHA are all investigating now to see what happened.
A man, who identified himself as the property manager, told Action News the workers were hired to work on the rooftop air conditioners.
He doesn't know how the lift fell.
That is all part of the investigation into how this catastrophic failure happened.