12/16/2011 11:34 am ET

Elevator That Killed Suzanne Hart Was Serviced Hours Before Accident; Buildings Department Investigates

The fatal midtown elevator accident that horrified New Yorkers Wednesday is being investigated by the New York City Department of Buildings, who is focusing their attention on repairs made to the elevator just hours before the tragedy.

Employees of Transel elevator were working on the same elevator that killed 41-year-old Suzanne Hart Wednesday.

"Workers from Transel were performing electrical maintenance work on the elevator involved in the accident hours before it malfunctioned," said buildings department spokesman Tony Sclafani. "This work has now become the focus of our investigation."

Hart, an ad executive at Young & Rubicam, was entering the elevator at 285 Madison Avenue when it suddenly lurched upward, pinning her between the car and the lobby walls, as two people inside the elevator watched in horror.

Hart was pronounced dead at 10AM Wednesday.

According to ABC News, the Department of Buildings says the force of the accident was so severe, it has raised concerns about the building's structural integrity.

The building remains closed Friday as officials make sure it's okay for office workers to return.

The Department of Buildings says it would be conducting a citywide sweep of elevators maintained by Transel, who has a long list of prominent clients including the Plaza Hotel and Carnegie Hall.

In September, 44-year-old Robert Moltio, a technician for Transel, was servicing an elevator on the 10th floor of a building at 230 West 38th Street on Sept. 23, when he fell to his death.

Although it remains unclear what caused the accident that killed Hart, elevator expert Patrick Carrajut tells Gothamist three likely causes for the accident:

"Experts don't speculate, but here are three primary possible causes. One would be mechanical error, and we don't know if a mechanic was on the job. Another possibility is failure in one of the relays or contactors. It's hard to describe to non-technical people, but if the contractor is energized or fails to de-energize, that can create a problem. Then the elevator would be allowed to move even though the door lock was not in the closed position.

"The third way would be a computer glitch. That would enable the cars to move with the doors open. But this is a highly unusual event. The fact that we've had two of these in the past two weeks is startling. There was another fatality in Orange County, California, when a woman tried to climb out of the elevator after a malfunction."

And meanwhile in Brooklyn, Jason Jones, an elevator mechanic, was charged with felony assault Thursday for not properly inspecting a lift that severely injured a 47-year-old woman last December.