Officials on Wednesday confirmed the deaths of three members of a family from a pipeline explosion that ripped through a residential suburb, bringing the total number of victims to seven.
Investigators used DNA to identify Lavonne Bullis, 85, and her son Gregory Bullis, 50, as victims of the Sept. 9 blast. Gregory Bullis' son, William James Bullis, 17, was identified after an examination of remains found at the family's home in San Bruno.
Staff worked quickly to make the identifications, said San Mateo County coroner Robert Foucrault. The state Department of Justice's missing persons unit performed the DNA tests.
Four other people died in the explosion nearly two weeks ago: Jacqueline Greig, 44, and her 13-year-old daughter Janessa Greig; their neighbor, Elizabeth Torres, 81, and 20-year-old Jessica Morales.
Four injured people remained at Saint Francis Memorial Hospital's burn unit; three were in critical condition, and one was stable, a hospital spokeswoman said.
The National Transportation Safety Board was investigating the cause of the explosion that leveled nearly 40 homes. It has trucked segments of the exploded pipe to its laboratories, and was conducting tests to determine if corrosion, material failure or other problems contributed to the leak and explosion.
NTSB officials said they would issue a preliminary report in coming weeks.
Meanwhile, Pacific Gas & Electric Co. has released its list of its 100 riskiest transmission pipeline segments, based on maintenance records and planned construction projects that could threaten to puncture specific lines.
The segment of pipe that blew up in San Bruno was not on the list. The company said it will wait to learn the cause of the explosion before determining if its inspectors missed something.