On Monday, September 21, a concrete electrical vault on Ventura Boulevard in Studio City was pushed roughly six to seven inches above the roadway just before 4 a.m., and as many as six cars slammed into the raised slab before anyone could stop them. About 2 p.m. that day, an underground fire near LAX sent flames shooting up from beneath the pavement at West Westchester Parkway and Loyola Boulevard, lifting the street itself. No injuries were reported in the Studio City incident, but it was not yet clear whether the driver seen in the LAX-area video was hurt. One Studio City driver believed his car was totaled, and the two events have reignited questions about the condition of the aging electrical infrastructure buried beneath Los Angeles streets.
The underground fire near LAX struck the afternoon of September 21, according to FOX 11 Los Angeles, which reported that LAPD and LADWP crews responded to the raised vault scene in Studio City after cars struck the displaced slab. Zacharias Macias, a licensed professional engineer and certified fire and explosion investigator with Macias Forensics, reviewed video from the LAX-area incident for the station. He has not personally examined the vaults involved in either case, but said the flames visible in the LAX footage suggest gas was involved.
How Heat and Age Combine Underground
Macias told the station that underground cable connection points are a common failure point, and that heat and repeated heating-and-cooling cycles can break down wire insulation over time. Degraded insulation can release gases into an electrical vault, and an electrical arc can then ignite that gas, he said. He described age as the underlying factor driving these kinds of incidents, with high heat compounding the risk: elevated temperatures increase electrical power consumption, which draws more current through conductors, and that increased current accelerates existing degradation already present in aging equipment.
Despite the mechanism he laid out, Macias cautioned that utility maintenance records and infrastructure upkeep are central to actually determining a cause, and he said an outside reviewer should participate in any review of that maintenance. He noted that underground electrical vault explosions are uncommon overall, even as he said utilities need to stay on top of inspections and maintenance. As of the FOX 11 report, the cause of neither Los Angeles incident had been officially determined, and LADWP had not responded to the station's requests for comment on either event.
A Summer of Strain on the Grid
The Studio City and LAX-area incidents followed a stretch of extreme heat that pushed demand across the region. LADWP urged customers to conserve energy on September 10, saying in a statement posted by ladwpnews.com that it continued to urge conservation “as high electricity demand continues due to extreme heat and humidity.” The utility said it had more than 90 field crews deployed across the city at the time to respond to any outages that occurred, a sign of how stretched the system can get during peak demand periods.
Separately, underground power work near Franklin and Argyle avenues in Hollywood is distinct from the LAX and Studio City incidents, but it underscores that underground vault and cable work has been an ongoing priority for the utility.
Not an Isolated Problem in the Region
Vault explosions have also been reported elsewhere in the region. Underground vault explosions have also surfaced outside Southern California in recent weeks: witnesses reported flames shooting from vault lids and loud booms in San Francisco's Financial District on October 1, and CBS News reported that four vaults near California and Front streets experienced eruptions that officials said were contained to the vaults themselves, with no injuries reported. ABC7 News also covered that October 1 incident, reporting street closures and a shelter-in-place order; PG&E confirmed that the blast was caused by a low-voltage underground cable.
Several underground explosions occurred inside an electrical vault near Toppers Pizza Place in Santa Clarita, according to CBS News Los Angeles, which reported that an investigation remained underway to determine what caused that incident.
What Officials Want Residents To Do
Amid the uncertainty over causes, engineer Zacharias Macias advised the public to stay away from any smoke coming from underground and to call 911 if they see underground smoke or hear popping or crackling sounds. With the cause of the Studio City and LAX-area incidents still undetermined and LADWP yet to respond to questions about either event, residents in neighborhoods with aging underground infrastructure are left watching the pavement a little more closely.
