Residents of the area packed a town hall meeting earlier to learn more about their homes, the investigation and the search for those still missing from the massive gas explosion.
"There are reports circulating that there may be additional fatalities," said Connie Jackson, the San Bruno city manager. "What we can tell you at this time is that search and investigation process is continuing."
Investigators are still trying to determine what caused the blast.
"We don't know what made that pipeline rupture," said Geisha Williams of Pacific Gas & Electric.
The explosion has raised concerns over similar gas lines laid across towns in the U.S.
"When you realize that some of this pipe was laid in 1948, others in the 50s , it raises a lot of questions," state Sen. Barbara Boxer said.
State and federal authorities said the section of gas pipeline that ruptured was ranked as high risk because it ran through a highly populated area.
"It's really hard to put into words the way you feel when you see a beautiful neighborhood and a whole section of it that just almost disappeared, and the remnants of the cars melted in the driveways," Boxer said.
Only a few residents received permission Saturday to return to their homes for a few minutes to get vital supplies, such as medicine.
"It is our expectation that the vast majority of homes will be accessible as of tomorrow," Jackson said.
Along with the seven confirmed deaths, more than 50 injuries have resulted from the fire. At the epicenter of the massive blast, there was a 15-foot crater created by the explosion that was so strong, it melted the asphalt. The 15-acre fire was fully contained shortly after 1 p.m. on Friday.
Friday, authorities were looking into reports by some San Bruno residents smelled gas in the area weeks before the massive explosion. Chris Johns, president of Pacific Gas & Electric, said the company had not received confirmation that there were reports of a gas smell in the area before the explosion, but said they were looking into it.
Federal investigators will analyze the pipeline's condition as well as its maintenance history, pressure levels and the safeguards put in place to prevent pressure from building up.
Transmission lines like the one that burst in San Bruno deliver natural gas from its source to distribution lines, which then carry it into neighborhoods before branching off into homes.
If you would like to help the residents affected by the San Bruno fire, monetary donations can be sent to:
American Red Cross Bay Area Chapter
85 Second Street, 8th Floor
San Francisco, CA 94105
You can also call (888) 4-HELP-BAY or visit the American Red Cross Bay Area Chapter's website to donate online, http://www.redcrossbayarea.org.
The Associated Press contributed to this report.