Neighbors closer to the blast site told Sekulich recently about smelling gas coming out of vents in the street, but she said she had not noticed it herself.
Many of the displaced said they were desperate for help.
"You felt like you were going to die," said Priscilla Tovar, 19, a student at Skyline College whose family home at 1631 Claremont Drive was destroyed. "It didn't hit me until today that we lost everything."
Tovar's cousin, Oselia Gomez, 22, said she heard a boom and "ran for my life" in her stocking feet as windows began exploding. A pet groomer at PetSmart, Gomez said she had moved to the house just two months ago from South San Francisco and did not have renters insurance.
She and family members ran for their lives. The blaze claimed their Chihuahua, Chula; their lizard, Izzy; and their cat, Carlos. But their boxer, named Boxer, was saved when she jumped into a neighbor's car.
Gomez hoped to secure financial help from PG&E or a public agency. "We struggled a lot to get approved for a house and then this happens," she said. "I'm just glad that everybody's OK."
As they waited to return to their homes, some spoke of what had drawn them to the neighborhood in the first place.
It was where Carlos Balagot, 29, and his wife bought their first home three years ago. The neighborhood was just about midway between his job in Mt. Pleasant and hers in San Francisco. "It felt like we were grown up," he said.
He said he was standing in his home Thursday when he heard the sound of the blast, a thunderous, rolling wave that reminded him of a rocket launch.
Balagot said he stood stunned and motionless until a piece of asphalt crashed through the roof and a ceiling beam fell to the ground. He ran into the backyard and jumped over neighbors' fences, one after another, until he was five or six houses away. From there, he walked to the street and watched his house burn to the ground. He called his wife and told her not to come home.
For the first time since the blast, authorities offered a limited tour of the disaster area. In the 900 block of Glenview Drive, houses were plastered with orange tags indicating that they were uninhabitable. In yards, signs warned away unlicensed contractors. In roads and driveways, charred cars had been numbered with spray paint.
Officials with the NTSB said the source of the explosion had not been determined.
The sheer power of the blast, however, was evident in the size of the crater it left — 167 feet long and 26 feet deep — as well as a 28-foot section of pipe that was hurled 100 feet, according to Hart, the agency's vice chairman.
Hart said the investigation will consider whether automatic shutoff values should be required on transmission pipelines that run through residential areas. "That is one of the questions that we'll be looking at," he said. He said the valves on each side of the explosion are manual.
The NTSB has set up an e-mail address to encourage residents and witnesses to contact the agency, which will take between 14 months and 18 months to complete its final report.
A fuller picture of some of those killed in the explosion emerged Saturday.
One of the victims, Jessica Morales, 20, had decided to go to her boyfriend's house in San Bruno to watch the first NFL football game of the season.
"I wish she wouldn't have been over there on that day," said her mother, Rene Morales, describing her daughter as an outgoing woman with an interest in fashion and design. She worked at a Baskin-Robbins and attended the Academy of Art university in San Francisco.
Also killed were Janessa Greig, 13, an eighth-grader described as the student body president of St. Cecilia School in San Francisco, and her mother, Jacquelin Greig, 44, who worked for the Public Utilities Commission, which regulates such utilities as PG&E.
"The irony was that she worked in the gas section" of a division of the commission, said Michael Peevey, president of the commission.
The girl's father and older sister were attending a back-to-school function at the time of the explosion.
The other four people confirmed killed in the blast had not been identified.
At the town hall meeting Saturday afternoon, the mood seemed generally supportive of city, police and fire workers, though less so of Geisha J. Williams, a PG&E executive.
Echoing a common concern, a resident wanted to know where gas lines are situated in the neighborhood. Williams replied that "security" issues prevented the disclosure of specifics, leading to an indignant outburst from the audience, which drew applause.
Ruane, the mayor, reminded the audience to be civil, saying, "We've gone through enough," which elicited louder applause.
Williams said the utility was trying to determine how to provide information about gas lines without compromising security.
She told the audience that the utility would "do everything we can do to make you whole.... We are not going to abandon San Bruno."
Times staff writers Paloma Esquivel, Tony Barboza and Victoria Kim contributed to this report.