As intense heat and smoke poured from the blazing basement of a house in West Oak Lane early Tuesday, the firefighters attacking the flames with a hose were ordered to get out.

The woman who lived there had been rescued. Another company was poised to go in through a back entrance to fight the flames. With conditions deteriorating, a commanding officer had said over the radio around 2:30 a.m. that that would be safer.

The firefighters began to retreat as directed, battling disorienting heat and blinding smoke. But Joyce Craig-Lewis did not emerge. Instead, the decorated 11-year veteran hit a Mayday button.

"I'm trapped! I'm trapped!" her frantic voice could be heard saying over the radio. Her fellow firefighters rushed back into the flames. But it was too late.

Craig-Lewis, a 36-year-old mother of two working an overtime shift, became the first female member of the Philadelphia Fire Department to die in the line of duty.

At a City Hall news conference, Mayor Nutter said the department had suffered a tremendous loss - a loss, he said, that extends to all Philadelphians.

"Joyce Craig-Lewis was a much-loved mother, daughter, and sister," said Nutter, flanked by a line of solemn-faced Fire Department commanders. "She loved her family, and she loved her job."

Fire Commissioner Derrick Sawyer described her as a "firefighter's firefighter," a veteran with a strong work ethic who prided herself on working at some of the city's busiest fire companies in order to "perfect her craft."

"Everybody is heartbroken," said Sawyer, who credited Craig-Lewis with helping to save the life of the 73-year-old widow who lived in the house.

"This brave firefighter gave her life attempting to save the life of an elderly woman," he said.

At Craig-Lewis' firehouse, where she has worked for two years, her colleagues hung black bunting over the fire engine door.

Joseph D. Schulle, president of Local 22 of the firefighters' union, said the department was "reeling" from the loss.

"The best compliment you can give a firefighter is that they are a very good firefighter. And that was certainly was her," he said. "She was well-respected and well-liked. She is going to be missed."

As officials mourned her death, investigators worked to determine what prevented Craig-Lewis from getting out of the rowhouse safely.

Sawyer offered a timeline:

At 2:29 a.m., the department received a report of a dwelling fire on the 1600 block of Middleton Street. The first units to arrive reported seeing no flames at the two-story brick house, but crews soon discovered a fire in the basement.

Basement fires pose dangerous tactical challenges for fire crews, Sawyer said. In battling them, firefighters must navigate narrow stairways of smoke and heat, funnels of combustion and flame.

Descending into the fire and smoke is like "running down into a chimney," Sawyer said.

Craig-Lewis was part of a three-member "attack team" advancing the first hose line into the fire.

The way it works, he said, is this: One firefighter works the nozzle of the hose, attacking the flames. Another helps pull the line. A third, an officer carrying a thermal-imaging camera, a flashlight, and a radio, directs.

"They act as a team," Sawyer said. "They go in as a team, and the goal is to come out as a team."

Sawyer said he did not know what position Craig-Lewis was working as the firefighters advanced into the basement.

After she and other members of the initial attack crew confronted heavy heat and smoke conditions, the commander decided to switch tactics, Sawyer said, and Craig-Lewis became trapped "in the process of withdrawing from the basement."

"After they withdrew, they realized firefighter Craig was missing, and they went in to search for her."

It was unclear how much time lapsed before others realized that Craig-Lewis was trapped.

"The strategy and tactics were sound," said Schulle, the union president. "When you're in the conditions we're talking about - high heat and zero visibility - there's a level of confusion."

A Fire Department official who listened to a recording of radio transmissions of the fire said Craig-Lewis could be heard issuing Maydays over three radio channels.

Rescue firefighters found Craig-Lewis in the dining room by a window, Schulle said. Colleagues performed CPR at the scene, and she was rushed to Einstein Medical Center, where she was later pronounced dead.

The mayor visited Craig-Lewis' family at the hospital and vowed a thorough review of the events leading to her death.

Investigators were examining Craig-Lewis' equipment, including a personal-safety alert system designed to signal when a firefighter is in danger. A distressed firefighter can manually trigger the alarm, which also goes off automatically if a firefighter remains motionless for more than 20 seconds.

It was not immediately known whether Craig-Lewis pressed her alarm or whether the device was functioning. Nutter said it remained "impossible to say" what happened until a full investigation was complete.

A graduate of Dobbins High School, Craig-Lewis had wanted to be firefighter from childhood, her family said.

"She was just all-consumed by this job," said her boyfriend, Jason Anderson, sitting in the living room of the family's Northeast Philadelphia home.

Craig-Lewis' son, Mekhi Green, 16, said his mother "loved her job."

An older relative held her 16-month-old daughter, Laylani.

Craig-Lewis started her career at Engine 9 in West Mount Airy, Sawyer said, but was later transferred to North Philadelphia's Engine 45, one of the busiest in the city. She worked there for several years before joining Engine 64 about two years ago.

On Tuesday, she had picked up an overtime shift at Engine 73, the first company to arrive at the Middleton Street fire.

When firefighters arrived, they quickly rescued the lone resident of the house, a woman who walked out into the rain, barefoot and in her nightclothes.

Seeing this, Fern Hall, who lives across the street, gave his neighbor shelter in his house.

Firefighters quickly put out the blaze. Then, Hall said, he saw a group of firefighters run out of the house, carrying a fallen colleague.

At the firehouse on Rising Sun Avenue where Craig-Lewis worked, colleagues held a Tuesday night vigil to remember the woman they described as a dedicated professional.

"She was a motivated worker. Loved her job. Loved talking about her kids," said Lt. Benny Hutchins, her supervising officer at Engine 64.

Inside, yellow tape was stretched across locker number 8, which colleagues had decorated with flowers, photos, and one of her work shirts, adorned with a small pink ribbon.

A pair of empty boots was set out on the floor.

215-854-2759 @MikeNewall

Inquirer staff writer Robert Moran contributed to this article.