Marketwatch reported: "Over the past two decades, there have been 846 'significant' accidents from onshore gas transmission, resulting in 33 fatalities, 173 injuries and $757 million in property damage, according to the U.S. Department of Transportation."
In perhaps the most infamous incident, on August 19, 2000, corrosion of a 30-inch diameter natural gas pipeline caused amajor explosion in Carlsbad, N.M., killing a dozen people, including four children, who were camping under a bridge that supported the pipeline over the Pecos River.
The cause of the PG&E explosion in the San Francisco middle-income suburb of San Bruno is not known. PG&E is checking reports that neighbors had reported a gas smell to the utility in recent weeks, and an engineering professor told KCBS that corrosion in a 24-inch transmission line was a possible source. (UPDATE: News sources put the size of the line at 30 inches).
A Wikipedia list of gas line accidents shows about 20 explosions that have caused fatalities in the U.S. over the last 40 years. While the gas industry says its safety record is outstanding compared to other means of transportation, industry observers told the Washington Independent that federal oversight by the Pipeline and Hazardous Materials Safety Administration is weak.
(09-10) 20:34 PDT SAN BRUNO -- A full day after the natural gas explosion and inferno that turned a San Brunoneighborhood into ash, the wreckage was still too hot for people to be let back in - but families of some of four people killed in the blaze got the news they had dreaded.
Investigators with search-and-rescue dogs spent Friday picking through the debris for more fatalities, with no new finds. The list of government agencies investigating the blast grew as a National Transportation Safety Board team arrived to take over the probe.
Representatives of Pacific Gas and Electric Co. said they did not know what caused a 30-inch, high-pressure gas pipeline to rupture at about 6:15 p.m. Thursday, setting off a firestorm that destroyed 37 homes in the Crestmoor neighborhood west of Interstate 280 and badly damaged eight others. Scores of people were treated at hospitals, and at least three were in critical condition Friday.
Officials said they had no estimate yet on the financial cost of the disaster. But the personal cost was immense.
The San Mateo County coroner identified two of the dead as Jacqueline Greig, 44, and he 13-year-old daughter, Janessa, whose house at 1670 Claremont Drive was destroyed.
Greig worked for the California Public Utilities Commission for 21 years and was a member of its Division of Ratepayer Advocates. She also was listed as a member of the natural gas committee on the National Association of State Utility Consumer Advocates.
"It's really unbelievably ironic," said Mindy Spatt, spokeswoman for TURN, an independent advocacy group for utility customers.
Marcel Hawiger, an advocate with TURN, said he knew Greig for a decade.
"She has been a tireless and wonderful advocate for consumers for many years. I'm just devastated - this is such a tragedy," Hawiger said.
Greig reviewed data that PG&E used to justify gas rates and reviewed energy projects to see if they were cost effective. One of the projects she was involved with was how PG&E went about charging for inspection of transmission pipes.
"She was such a nice person," Hawiger said, "She was always such a pleasure to work with."
Also killed was 20-year-old Jessica Morales, the coroner said.
The coroner has not identified the fourth victim. But relatives of 81-year-old Elizabeth Torres, whose house at 1660 Claremont Drive was leveled, fear it may be her. A body was found outside her home, and the coroner was checking dental records, relatives said.
Torres' daughter-in-law, Teresa Whorton, said she was born and raised in San Francisco, has nine children and loves flowers and plants.
"She was a kind, loving person," Whorton said. "Very caring and sometimes stubborn. She was a Capricorn. She loved her kids.
"Everybody on the block knew her and cared about her."
According to her family, Torres - who uses a wheelchair - had been smelling gas lately, and she was at home Thursday awaiting PG&E crews to arrive and check her gas stove, which wasn't working.
PG&E was at the center of the investigation into how its pipeline failed. The pipe was a main transmission line that fed off to smaller distribution lines, which then branch into homes.
When it blew up Thursday evening at Claremont and Glenview drives, it left a 30-foot-wide crater. A large section of the pipe was hurled from the ground, "indicating great magnitude," said Christopher Hart, a spokesman for the National Transportation Safety Board.
It took crews at least a half-hour to shut down the gas flow to the broken line.
Geological reports registered a shaker of 1.3 magnitude at the time of the explosion, which officials believe was from the pipeline detonating.
Several residents have said they smelled gas in the neighborhood in the days before the explosion and that PG&E trucks had been in the area. Utility President Chris Johns said he could not confirm that, but that PG&E was checking its records.
By evening, coroner's investigators and emergency responders had searched 95 percent of the affected homes for victims, without finding anyone. The remaining homes were still too hot to approach. No one is known to be missing, authorities said.
At least 52 people suffered burns, smoke inhalation and other injuries, and three of them were in critical condition with third-degree burns, authorities said.
"There is still a dark cloud over this city," San Bruno Mayor Jim Ruane said. "You've heard the numbers."
City Manager Connie Jackson said the city was a "strong and resilient community. We are proud to live here, and we will be proud to respond and to restore the vitality and the safety that San Bruno is known for."
She said the most devastated streets were the 1600 and 1700 blocks of Claremont Drive, the 900 block of Glenview Drive, the 1700 block of Earl Avenue, the 1100 block of Fairmont Drive and the 2700 block of Concord Way.
Lt. Gov. Abel Maldonado, who is acting governor while Gov. Arnold Schwarzenegger is in China on a trade mission, briefed President Obama on the disaster. He said 30 additional fire engines were deployed Friday to supplement the 67 engines that responded Thursday night.
More than 100 people were evacuated from the area soon after the explosion, most of whom were still being kept away at midday. After the evacuations, police confronted a suspected looter who assaulted an officer and ran off, but was chased down and arrested, said San Bruno Police Chief Neil Telford.
Some 200 firefighters from agencies around the area responded to the blaze, joined by air tankers that dropped retardant on the fire. Millbrae Fire Chief Dennis Haag, the incident commander, said Friday, "As devastating as this was, it could have been so much worse."
He said the first engine on scene got within about a 100 yards of the fire and "then had to stop because their windshield cracked (from the heat). As they pulled back, they saw paint bubbling on the cars in the street."
Haag said the devastation was like nothing he'd seen in his 31 years as a firefighter.
The explosion damaged a water main in the area, making it harder for firefighters to fight the blaze, Haag said. Firefighters had to skip over hydrants and lay longer sections of hose, he said.
"I lost count of how much hose I drove over last night," Haag said. "You're not supposed to do that, but sometimes you can't avoid it. Adapt and overcome, that's our motto."
Among those promising to investigate the blast are state legislators, and the San Bruno Police Department is treating the area as a crime scene - another reason residents were not being allowed back in.
"Until we know what caused it, we want to preserve anything of evidentiary value," Telford said.
Some residents were losing patience. Many who took refuge at a nearby shelter had no idea what happened to their homes.
Charles Cresci, 79, lives on Windsor Court and knows his house is intact, but he's still an evacuee.
The police "won't even let me back in to get my medicine," Cresci said.
"We're well aware people want to get back to their homes and we want to get them there," Telford said as he fielded some often-testy questions from a group of Crestmoor homeowners at the shelter. "But we went them to get back safely."
Chronicle staff writers Will Kane, Victoria Colliver and Henry K. Lee contributed to this report.