PG&E found to be at fault in January house explosion
Nine months after a home on South George Washington Boulevard exploded, the California Public Utilities Commission released its investigation report, finding that Pacific Gas and Electric Co. is at fault for the faulty installation of a pipeline.
Third-party engineering firm Exponent – hired by PG&E to probe the cause – reported to the CPUC that the explosion was caused by ignition of natural gas accumulated in the home. The source of that gas was a leak in a 4-inch Aldyl-A (type of plastic piping) gas main that ran along the shoulder of the road in front of the house; the leak was located at a joint in the main, according to the report.
“The direct cause of the leak was a fabrication error during original installation of the main in late 1973 or early 1974,” it’s stated in the report. “Specifically, the end of the upstream pipe comprising the joint had not been fully faced flat and square with the axis of the pipe. Thus, when this pipe was butt-fused to the downstream pipe, a portion of the contact plane failed to melt and fuse, forming crack-like defect open to the interior of the pipe on the eastern side of the joint.”
The home in the 2200 block of South George Washington Boulevard exploded at about 6 a.m. Jan. 12, while owner John Lee Clark was making coffee and his girlfriend Ravin Skondin was showering.
Clark was blown out of the home, but returned through the fiery debris to carry out Skondin. All that was left standing was the shower stall. Clark suffered second-and third-degree burns to 30 percent of his body, and Skondin and Clark’s dog also suffered injuries.
A couple weeks after the explosion, PG&E replaced one mile of pipe along Bogue Road and South George Washington Boulevard. In earlier interviews, PG&E public information officer Paul Moreno wouldn’t say if the repairs were in response to the explosion, but that the project was not included in the original three-year plan to replace pipes throughout the service area. He said it was being done “in an abundance of caution.”
According to Appeal-Democrat archives, PG&E turned over its investigative findings to the CPUC in April or May. The Appeal-Democrat has been asking the CPUC for the investigative report monthly. The commission’s Terrie Prosper, director of news and outreach, usually took days and sometimes weeks to respond to emails and phone calls; her last returned email was in July.
Only Wednesday, at the request of the Appeal-Democrat, did the CPUC provide the investigative report, dated Sept. 12. The CPUC did not respond to follow-up questions.
CPUC, Exponent report
The report estimated that the blast caused around $351,500 worth of property damage, including the $1,500 estimated cost of gas release.
The report also stated that CPUC’s Safety and Enforcement Division reviewed documentation and found that leak surveys on Aug. 14, 2010, and June 9, 2015, identified no leaks.
The exterior portion of the faulty pipe’s joint had fused sufficiently to remain pressure-tight until sometime between the last leak survey in June 2015 and the morning of January 12, 2017.
“Given the size of the ultimate leak, the final breach appears to have occurred within hours of the explosion,” according to the report. “Otherwise, the leak, which released odorized gas and caused bubbles in puddles, likely would have been detected.”
The bad fusion in that one part of the line caused a crack to open to gas pressure on the inside of the pipe, the report states, growing for 43 years from concentrated stress such as from rocks, tree roots, or ground movement. There is no evidence to indicate that stress from a dig-in or heavy vehicle traffic were factors.
The migration path of the leaking gas was confined by the driveway pavement and garage slab, forcing most of the migration horizontally and limiting the amount of released gas into the air. The migrating gas most likely entered the crawlspace through pervasive ground cracks in the drier soil within, according to the report.
Exponent found that PG&E’s emergency response to the explosion and fire was consistent with documented procedures, applicable regulations, and industry best practices.
“Had PG&E been able to stop the gas flow instantaneously after the explosion, the outcome would have been materially the same,” according to the report.
Clark and Skondin’s attorney, Douglas Adams of Sacramento, said the report is a step in the right direction.
“I’m pleased that they reached the right conclusion. This explosion and fire was caused by PG&E. My clients are continuing to suffer as a result of their improper conduct,” Adams said Thursday.
Spokesman Greg Snapper said PG&E was provided with the CPUC report – finalized last month – just Thursday.
“We want our customers to know that we have been hard at work since the incident occurred in January,” Snapper said in an email. “Our safety actions include regular leak inspections of our entire natural gas system using the best technology available, rapid response to gas odors, replacement of pipe and finding and fixing leaks.”
He noted PG&E’s safety actions, including:
– Pipe replacement along South George Washington and Bogue Road.
– Regular leak inspections in Yuba City and across its entire system.
– Rapid response to any odor call received.
– Exponent was immediately brought in to conduct a thorough investigation.
Snapper said that PG&E has reviewed leak records for the gas distribution system for fusion-related leaks, looking to see what trends or information could indicate potential fusion issues.
“We’re using this to inform our system-wide inspection and pipeline replacement program,” he said. “Leaks that appear to be a sign of fusion joints are further investigated and action taken to keep families and businesses safe.”
He noted that PG&E practices an intensive operator qualifications program overseen by the CPUC that ensures every gas worker performing pipeline installations is properly trained in the area of pipe fusions, among other required duties.
When asked if PG&E plans to financially aid Clark and Skondin, or what the next steps in the incident are, Snapper replied, “We’re going to continue supporting that community.”
Adams said his clients are still suffering from the traumatic event.
“Our clients are still recovering from and undergoing medical treatment for injuries, and we’re gathering evidence necessary to prove their claims,” Adams said.
CONTACT Rachel Rosenbaum at 749-4771 and on Twitter @RaeRosenbaum.