Two hours after a road crew accidentally struck a natural gas line in the unincorporated Ashland neighborhood near Hayward earlier this month, Pacific Gas and Electric Co. had finally stopped the leak.
Road workers had left the immediate area, but no official evacuation orders had been issued, despite the possibility that a dangerous amount of highly combustible gas remained trapped in nearby homes.
Minutes later, a violent explosion erupted, obliterating multiple homes and injuring six people, sending three to the hospital.
The sequence of events has experts questioning whether local authorities and PG&E, which has a troubled history of gas-safety incidents, took the appropriate steps to keep residents safe.
Robert Hall, a recently retired director of pipeline investigations for the National Transportation Safety Board, faulted the utility for failing to stop the leak more quickly. He said that even after PG&E shut off the release, utility crews and local fire officials, who also responded to the damaged pipeline, should have been aware that gas could have remained trapped underground or inside structures.
“I do believe they should have been getting people out of the homes for safety’s sake,” said Hall, who has overseen past federal investigations into PG&E.
PG&E and the Alameda County Fire Department have said they make evacuation decisions collaboratively on a case-by-case basis, and that further investigation is needed to answer whether residents should have been told to leave. Both the utility and the fire department declined to answer additional questions from the Bay Area News Group about their response to the leak.
In a brief statement to this news organization, PG&E offered “thoughts and prayers” to “all who have been affected by this incident.”
The explosion is the latest in a series of gas-safety incidents involving PG&E, evoking memories of a 2010 blast in San Bruno that killed eight people and destroyed dozens of homes after an aging pipeline owned by the utility ruptured. Investigations into those incidents found slow response times and other operational failures.
In response to the San Bruno tragedy, the California Public Utilities Commission, which is investigating the latest explosion, began fining gas companies and utilities for violating state and federal gas safety rules.
Over the past decade and a half, the agency has cited PG&E, which serves 4.5 million Northern California gas customers, 19 times for gas violations totaling more than $35 million. For comparison, Southern California Gas Co., which serves more than 20 million customers, has been cited six times, with $6.2 million in penalties.
The commission fined PG&E $1.6 million after an employee failed to follow the correct procedure for cleaning a pipeline in Napa County in 2022. That incident resulted in the death of a utility worker. PG&E was also fined $600,000 for allowing an aging copper gas pipeline in San Jose to corrode, leading to a 2018 explosion after a resident lit a match in their bathroom.
In 2019, the utility responded to a gas leak that, like the recent Alameda County accident, ignited after a contractor cut through an underground line, causing $10 million in property damage. In a subsequent report on the incident, the NTSB faulted PG&E for failing to quickly locate the valves needed to shut off the gas release.
“It took PG&E about an hour to identify the specific locations of the valves that needed to be isolated,” the agency wrote.
Hall said he was aware of at least four NTSB investigations into PG&E, out of around 150 nationwide since 1970.
PG&E did not respond to questions about the past incidents.
An initial report on the Alameda County explosion by the NTSB, which is continuing to investigate the incident, found that when the blast ignited at about 9:35 a.m., PG&E was repairing the gas line after it had been damaged at about 7:30 a.m. by a third party doing grading work for a county-contracted road improvement project.
According to PG&E, the utility identified two separate leaks along East Lewelling Boulevard, stopping one at 8:18 a.m. and the other at 9:25 a.m., just before the blast.
The Alameda County Fire Department said it arrived on the site shortly after the rupture at 7:50 a.m. The department said it “checked in with authorities on the scene” and was “cleared” by officials on scene a few minutes later. The Alameda County Sheriff’s Office said it was not contacted about the leak until after the blast. County officials did not respond to questions about the leak.
Hall said that, given the long duration of the leak, utility crews and first responders should have quickly sought to determine whether gas remained trapped underground or inside nearby structures, adding that natural gas often loses its identifiable odor after seeping through soil.
“I’m concerned the fire department was told to leave,” he said.
Under federal regulations, utilities must maintain written procedures for responding to gas leaks and other pipeline emergencies. PG&E declined multiple requests by this news organization to provide its emergency gas plan, which is supposed to include protocols for emergency shutdowns, valve shut-offs and pipeline pressure reductions, among other actions.
However, emergency guidelines published in 2023 by the Pipeline Association for Public Awareness, which includes PG&E as a member, outline recommendations for evacuation distances after gas leaks based on pipeline size and pressure. It remains unclear whether county authorities and PG&E should have instructed residents to evacuate in accordance with those recommendations.
The guidelines also stress that leak responders should seek to eliminate all potential ignition sources and, if necessary, shut off electrical power to the area — steps that do not appear to have occurred before the explosion. The association lists cell phones, emergency radios, vehicle engines and construction equipment as possible ignition sources.
Despite those warnings, a striking video of the blast captured by a neighbor’s doorbell camera shows a worker operating what appears to be an excavator as a home behind it detonates. It remains unclear who was operating the heavy machinery.
“The most important thing you can do on a job site, if there’s something critical: stop,” said Brian Aanestad, an underground construction consultant in San Diego County who serves as an expert witness in gas-safety lawsuits. “You have to stop.”
In a statement the day after the blast, Oakland-based Redgwick Construction Company said its subcontractor immediately stopped work after cutting the line. The firm alerted PG&E, which instructed workers to leave the area, according to the statement. The road company, hired by the county to complete a road improvement project in the neighborhood, said its crew was working two blocks away at the time of the blast.
“I don’t know what PG&E was doing at that time,” said Redgwick Vice President Travis Miller in a phone call.
Miller declined to answer additional questions about the leak. PG&E did not answer whether one of its workers was operating the excavator.
In a statement, Redgwick Construction said the line’s depth “deviated from the required code specifications.” A ¾-inch-diameter steel line and a 2-inch steel gas main at the site of the blast were installed in the 1940s, according to the NTSB.
Hall said the line’s depth could have contributed to why it was cut. He said the NTSB’s investigation is expected to be completed in 12 to 24 months. While the agency has little enforcement authority, its findings could inform future penalties brought by other regulators.
“The important facts,” Hall said, “are the two-hour response, the release of the fire department without verifying there wasn’t gas in the structures, and the lack of evacuation of the closed-in houses.”
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