UPDATED 01/09/12 4:15 p.m.

CHICAGO (CBS) — City officials said Monday that a door left open by a Lakeview couple fleeing a high-rise fire helped spread the deadly blaze and an elevator malfunction slowed firefighters’ ability to get to the fire right away.

Meantime, residents of the building were upset to learn Monday that fire safety requirements that might have saved McCoy’s life were recently pushed back three years.

As CBS 2’s Susanna Song reports, the fire broke out just after 2 a.m. Sunday at a 21-story rental apartment building at 3130 N. Lake Shore Dr. – the corner of Lake Shore Drive West and Briar Place.

shantel mccoy 0108 Officials: Open Door Helped Spread Fatal Fire In Lakeview

Shantel McCoy, 32, died from smoke inhalation in an extra-alarm fire at her apartment building in the Lakeview neighborhood on Jan. 8, 2012. (Family Photo)

Twelfth floor resident Shantel McCoy, 32, died in the fire when she unwittingly got on an elevator to the 12th floor, where the fire broke out, to be greeted by intense heat and smoke. Nine others, including two firefighters, were injured. Most of the residents were asleep when the fire broke out.

Fire Department spokesman Larry Langford said the couple who lives in the apartment where the fire started told investigators they propped the door open with a rug when they left to get away from the fire so their pets – a cat or cats – could get out too. As a result, fire and smoke were able spread into the hallway.

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In addition, as CBS 2’s Dorothy Tucker reports, residents of the building learned that McCoy would not have been able to ride the elevator had the building been retrofitted with new fire safety features under an ordinance approved by the City Council eight years ago. The ordinance’s fire safety requirements were supposed to go into effect this year, but aldermen recently voted to push back the mandate another three years.

In 2004 — a year after a high-rise fire at 69 W. Washington St. killed six people — the City Council passed an ordinance that required owners of residential high-rise buildings to make a number of “life safety” improvements by Jan. 1, 2012, such as installing hard-wired communications and alarm systems that would be able to shut down elevators and send them to the lobby in the event of a fire. But last month the City Council gave property managers an extension until 2015 after complaints about the costs of the ordinance.

The building is managed by Planned Property Management. Officials for the company declined comment on Monday. Several City Council members also declined to talk about the fire safety ordinance.

Ald. Tom Tunney (44th), whose ward includes the building and who backed the three-year extension of fire safety requirements for residential high rises, sent a prepared statement offering his condolences to McCoy’s family.

“Our hearts go out to the family and friends of Shantel McCoy and those injured in Sunday’s fire at 3130 N. Lake Shore Drive.” Tunney said. “In a tragic instant, a young life was taken from the world just as she was starting anew in our City.”

McCoy’s mother, JoAnn McCoy, said her daughter moved to Chicago from Philadelphia last March to start a new life, and she worked for Wirtz Beverages. McCoy’s mother spoke to CBS 2’s Dana Kozlov Sunday night.

“I have many a question, yes I do,” JoAnn McCoy said. “Shouldn’t the elevators have shut down for her not to able to get on there? You know, it’s a fire.”

WATCH: Tips On Surviving A High-Rise Fire

It appeared Monday morning that either a candle left burning or an electrical problem in the 12th floor unit where the fire broke out was to blame for the deadly blaze, but an official cause had not been determined as of Monday afternoon.

McCoy was found in an open elevator stopped at the 12th floor. Investigators say she was not in the elevator to escape the fire, but was simply returning home and taking the elevator up to her apartment, not knowing a fire had broken out on that floor and spread to the hallway.

“It appears she came home last night. She had some carry-out food with her in her purse and got in the elevator, went to her floor – which is the 12th floor — the doors opened up and she was hit with the heat and smoke,” said Fire Media Affairs Chief Joe Roccasalva.

When the elevator doors opened, McCoy was met by 1,500-degree heat and poisonous gas. She was pronounced dead at St. Joseph Hospital a few blocks south.

“I was surprised by that,” said James Johnson, who lives on the 19th floor of the building. “But, you know, when you don’t have an integrated fire control system, … I don’t know it would have been stopped.”

City officials also said Monday that firefighters’ efforts to put out the blaze were slowed because the elevators did not return to the lobby when firefighters inserted a key into the system. Langford said the delay “did not contribute to the death of Miss McCoy,” who apparently entered the elevator before firefighters arrived.

“The elevator recall did not work,” Langford said. “Why, I don’t know.”

Langford said, as a result, firefighters had to walk up at least 10 flights of stairs to fight the fire, carrying heavy gear the whole way.

“It delayed … getting water to the fire,” Langford said. “The system did not work. They weren’t able to bring them down.”

“When the firefighters get up to the fire floor, they’re more fatigued by carrying all that equipment up and their efficiency is probably lower at fighting the fire. They’re spent just getting there,” Langford added. “It’s not a good thing.”

In a statement Monday afternoon, the city’s Buildings Department said no outstanding code violations were found at the building.

“Elevator inspectors were at the building today and all elevators are working properly,” the department said. “The elevators at 3130 N. Lake Shore Drive are equipped with manual recall, a feature common in buildings designed before 1975. The Department of Buildings and Fire Department speculate that the heat on the 12th floor activated the elevators’ safety circuits, stopping the elevators from returning to the first floor, despite firefighter’s manual recall.”

Recent building inspection reports showed the building had several past code violations related to the elevators.

READ: City of Chicago High Rise Safety Guide

A building inspection report from Nov. 4, 2011, cited two dozen violations related to the elevators, including an order to repair the fire recall system for the elevators. But less than two weeks later, a follow-up inspection found all problems had been addressed and no violations were found.

A similar inspection report in November 2010 also found two dozen violations related to the elevators, nearly identical to the 2011 report. But those violations were also addressed within a week, according to the 2010 report.

An autopsy performed on Sunday found McCoy died of carbon monoxide intoxication and inhalation of smoke and soot from an apartment fire and her death was ruled an accident, according to the Cook County Medical Examiner’s Office.

As Sunday’s fire raged, neighbors as far as half a mile to the south were kept awake for hours by the response, which included a helicopter. Meanwhile, responding firefighters were forced to climb the stairs to get to the blaze because the elevators did not return to the first floor.

They later found McCoy’s body.

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