NEW YORK (AP) -- City hospital officials said they were shocked by surveillance footage showing a woman falling from her chair, writhing on the floor and dying as workers failed to help for more than an hour.

Surveillance video shows a woman lying on the hospital floor for almost an hour before anyone helped her.

Esmin Green, 49, had been waiting in the emergency room for nearly 24 hours when she toppled from her seat at 5:32 a.m. June 19, falling face-down on the floor.

She was dead by 6:35, when someone on the medical staff, flagged down by a person in the waiting room, finally approached, nudged Green with her foot and gently prodded her shoulder, as if to wake her.

The staffer left and returned with someone wearing a white lab coat who examined her and summoned help.

Until the staffer's appearance, Green's collapse barely caused a ripple. Other patients waiting a few feet away didn't react. Security guards and a member of the hospital's staff appeared to notice her prone body at least three times but made no visible attempt to see whether she needed help. Watch the surveillance video »

One guard didn't even leave his chair, rolling it around a corner to stare at the body and then rolling away a few moments later.

Green, who had been involuntarily committed the previous morning and had waited overnight for a bed, stopped moving about half an hour after she collapsed.

The New York City Health and Hospitals Corporation, which runs the hospital, said six people have been fired as a result of the incident, including security personnel and members of the medical staff.

Green's medical records raised the possibility that someone might have tried to cover up the circumstances of the death.

They contained notations indicating that she was up and about during the time in which the video shows her dying on the floor.

"We are all shocked and distressed by this situation," HHC's president, Alan Aviles, said in a statement. "We express our deep regrets to the patient's family and will ensure a thorough investigation to answer any questions that remain."

Details of the death were disclosed by the hospital June 20, but the case largely remained unnoticed until the video became public.

The psychiatric unit at Kings County Hospital had been a subject of complaints by advocates for the mentally ill.

A state agency, the New York State Mental Hygiene Legal Service, filed a lawsuit a year ago, calling the psychiatric center "a chamber of filth, decay, indifference and danger."

Patients, the suit said, "are subjected to overcrowded and squalid conditions often accompanied by physical abuse and unnecessary and punitive injections of mind-altering drugs."

"From the moment a person steps through the doors," it added, "she is stripped of her freedom and dignity and literally forced to fight for the essentials of life."

The suit was especially critical of the hospital's emergency ward, saying it is so poorly staffed that patients are often marooned there for days while they wait to be evaluated.

Sometimes, the unit runs out of chairs, according to the lawsuit, forcing people to wait on foam mats or on the waiting room floor. The suit also claims that bathrooms are filthy and filled with flies, and that patients who complain too loudly are sometimes handcuffed, beaten or injected with psychotropic drugs.

The office of the city's medical examiner said it was still trying to determine why Green died. She had been brought to the hospital suffering from agitation and psychosis, city officials said.