Sept. 12 (Bloomberg) -- Authorities said as many as four people were still missing today as investigators searched for clues to the cause of a PG&E Corp. natural-gas pipeline blast that destroyed 37 homes in a San Francisco suburb.
The death toll remained at four and skeletal remains that were found at the site of the disaster yesterday were being tested to determine their origin and identity, Michelle Rippy, senior deputy coroner for San Mateo County, California, said today in a phone interview.
Some residents were being allowed to return to their homes today after the Sept. 9 pipeline rupture and fire that burned a 15-acre residential area in San Bruno.
Investigators for the National Transportation Safety Board, which is overseeing the probe into the cause of the explosion, began gathering evidence and making measurements yesterday at the site, which is about two miles (3.2 kilometers) west of San Francisco International Airport.
The blast left a crater in the street 167 feet (51 meters) long by 26 feet wide, NTSB Vice Chairman Christopher Hart said at a press conference yesterday. Federal authorities discovered that a 28-foot piece of pipe that was blown about 100 feet out of the ground was made of sections welded together, Hart said. Officials will be looking at why the pipe was constructed that way, he said.
California lawmakers pressed investigators, who said it may be 18 months before they can conclude their work, to quickly determine the cause of the incident.
“We cannot wait for answers to this,” U.S. Senator Barbara Boxer told reporters yesterday in San Bruno.
PG&E, based in San Francisco and California’s largest utility owner, inspected the pipeline in November and performed an annual so-called gas-leak assessment in March, Geisha Williams, senior vice president of energy delivery of PG&E’s Pacific Gas and Electric utility said yesterday during an interview.
Williams declined to discuss the results of the two inspections.
PG&E has not been able to confirm reports that residents made calls to the utility complaining of a gas smell in the days before the explosion, Chris Johns, president of PG&E’s Pacific Gas and Electric, said.
The utility has searched about two-thirds of its phone records from the neighborhood from Sept. 1 through Sept. 9, Johns said. Utility crews weren’t at the site at the time of the blast, he said.
The company has $992 million in liability insurance for damages caused by fire, according to a public filing on Sept. 10.
“If it is ultimately determined that we were responsible for the cause of the incident, we will take accountability,” PG&E said in an e-mailed statement.
Financial results “could be materially adversely affected” if, after the explosion is investigated, insurance is insufficient or unavailable, PG&E said in the filing.
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