Military report says 'one in a million' live fire malfunction rained shrapnel on California highway

LOS ANGELES (AP) — A “one in a million” malfunction during a live fire demonstration over Camp Pendleton last October led to a misfire that rained shrapnel on Interstate 5, striking two California Highway Patrol vehicles, a U.S. Marine Corps investigation found.

An artillery shell exploded over the highway that serves as the main corridor between Los Angeles and San Diego during a celebration of the 250th anniversary of the Marine Corps, attended by Vice President JD Vance and Defense Secretary Pete Hegseth. Nobody was hurt, and investigators ruled out any negligence or wrongdoing by Corps members.

The day before the event, Democratic Gov. Gavin Newsom called the planned demonstration with live artillery dangerous and unnecessary, and he ordered I-5 to be closed during it. That closure drew condemnation from the White House and other Republicans, and the Marine Corps said the exercises wouldn't endanger motorists.

In a 666-page report dated Dec. 19 and first reported on Monday, the Marines concluded that there “is no definitive answer” to why an M795 high explosive round detonated early at an altitude of about 1,480 feet (450 meters) during the Oct. 18 demonstration. Such a premature detonation is “beyond reasonable expectations and should not have happened, but it did,” the report says.

“It is manufactured to a tolerance of one defect in a million,” according to the report.

Organizers planned to fire 60 rounds of live artillery in 5 minutes over the highway, using six howitzer weapons, according to the report. But a round in the first volley of shots failed and detonated early, and the rest of the demonstration was canceled, the report said.

Days after the malfunction, 26 California U.S. House members and the state’s two senators sent a letter to Hegseth asking who decided to shoot live artillery over the freeway and how authorities prepared for the safety risks.

“We’re thankful to the Marines for their thorough and precise investigation — in stark contrast to the dangerous and performative demands by JD Vance and Pete Hegseth to shoot live ammunition over a civilian area for their entertainment,” Diana Crofts-Pelayo, a spokesperson for Newsom’s office, said in an email Tuesday.

Newsom announced the highway closure in a statement after practice rounds were fired a day ahead of the celebration. The governor described the live fire exercise as a show of force meant to intimidate Trump’s opponents, thousands of whom were demonstrating at “No Kings” protests in and around San Diego that day.

“Firing live rounds over a busy highway isn’t just wrong — it’s dangerous,” Newsom wrote at the time.

The Marine report concluded several factors could have contributed to the malfunction, including the howitzer guns being too close together when fired and the "potential presence of anomalous electromagnetic energy in the vicinity.”

“What was different from the thousands of times before this event employing the same shell-fuze combination, weapons system, and highly trained Marines? There is no definitive answer," the report said.

The event at Marine Corps Base Camp Pendleton featured aircraft, ships, and amphibious assault vehicles to celebrate the anniversary.

“It will be a good show regardless of who shows up,” Gen. Eric Smith, commandant of the Marine Corps, said in an Oct. 14 email to Brig. Gen. Garrett “Rainman” Hoffman, of the White House Military Office, according to the investigation.

The first round launched at 1:46 p.m. from M777 howitzers on a beach west of Interstate 5. That artillery round detonated midflight near I-5 southbound, sending shrapnel flying toward a CHP motorcycle and another unoccupied patrol vehicle, according to the CHP report. The vehicles had been part of Vance's protective service detail and were waiting near a highway ramp after securely getting Vance where he needed to be, the report said.

An officer described hearing what sounded like “pebbles” falling on his motorcycle, and finding shards nearby. Other shrapnel struck and left a dent on the hood of another patrol vehicle.

CHP sergeants conducted a safety sweep and didn't find any other pieces of metal in the highway lanes, the report said. Both sides of the highway were reopened about 30 minutes later.

Multiple people interviewed for the Marines investigation said they wouldn’t have changed anything about the event. Some noted a drill the day before did not have any problems and routine safety checks were done more than usual.

Associated Press reporters Ed White in Detroit and Rebecca Boone in Boise, Idaho, contributed to this report.

This photo provided by the California Highway Patrol shows shrapnel from live artillery that hit patrol vehicles during an Oct. 18, 2025, military celebration in San Diego. (California Highway Patrol via AP)

This photo provided by the California Highway Patrol shows shrapnel from live artillery that hit patrol vehicles during an Oct. 18, 2025, military celebration in San Diego. (California Highway Patrol via AP)

FILE - Vice President JD Vance speaks during an event to mark the upcoming Marine Corps' 250th anniversary, Oct. 18, 2025, on Marine Corps Base Camp Pendleton in Camp Pendleton, Calif. (AP Photo/Gregory Bull, File)

FILE - The entrance to Marine Corps base Camp Pendleton is seen on Sept. 22, 2015, in Oceanside, Calif. (AP Photo/Gregory Bull, File)

So much for being champions of the world.

Chelsea played more like also-rans than world beaters on Tuesday night, losing 3-0 at home to Paris Saint-Germain in the return leg of their Champions League last-16 game for a staggering 8-2 defeat on aggregate.

Chelsea fans proudly displayed a banner reading “Champions of the World” before kickoff on Tuesday at Stamford Bridge. The stark reality painted a different picture.

Chelsea collapsed with late goals last week in a 5-2 loss and imploded with early goals this time, trailing 2-0 inside 15 minutes.

That banner referred to Chelsea's victory in the Club World Cup final last July, when Chelsea beat PSG 3-0.

Some of the home fans started booing during the first half of Tuesday's loss and ironically cheered their players when they completed a pass.

The defeat could have been worse, but some Chelsea fans had already seen enough and started to leave after PSG's third goal in the 62nd minute.

Chelsea coach Liam Rosenior looked on perplexed, chewing his pen or biting his nails as PSG passed his side off the field at will. The Englishman only joined Chelsea in January after leaving French club Strasbourg.

“In the Champions League you don’t deserve better if you mistakes against a very good team," he said. “The first goal is a mistake from us ... (It’s) impossible to concede so many goals.”

Chelsea hired him after parting company with Enzo Maresca, who won Conference League and Club World Cup trophies.

Last week, Rosenior surprisingly selected goalkeeper Filip Jörgensen ahead of Robert Sánchez and it was Jörgensen's error that led to PSG's third goal in the 74th minute of that game.

On Tuesday, he reinstated Sánchez and dropped central defender Wesley Fofana, replacing Fofana with 20-year-old center back Mamadou Sarr.

That didn't work, either, as it was Sarr's sloppy defending that allowed Khvicha Kvaratskhelia to score PSG's first goal after six minutes.

This was a third straight defeat for Rosenior, whose team is sixth in the Premier League with eight games left. There is still a trophy on offer, however, with Chelsea into the FA Cup quarterfinals.

Chelsea right back Trevoh Chalobah was stretchered off late on with an ankle injury.

Rosenior said it was too early to determine how bad the injury was.

Chelsea’s players performed their pre-match huddle just inside PSG's half. PSG’s players did not seem to mind as they jogged casually past Chelsea’s players moments before the start.

Under Rosenior, Chelsea’s players have made a habit of gathering in a circle around the ball on the halfway line in the moments before the first and second halves begin in a display of unity.

Before the Premier League match against Newcastle last Saturday, the huddle took on a new dimension. When referee Paul Tierney took hold of the ball next to the center circle he soon found himself surrounded by the Chelsea team.

AP soccer: https://apnews.com/hub/soccer

Chelsea players huddle before the Champions League soccer match between Chelsea and Paris Saint-Germain in London, England, Tuesday, March 17, 2026. (Adam Davy/PA via AP)

Paris Saint-Germain players celebrate after PSG's Bradley Barcola scored his side's second goal during the Champions League soccer match between Chelsea and Paris Saint-Germain in London, England, Tuesday, March 17, 2026. (AP Photo/Kin Cheung)

PSG's Willian Pacho, left, challenges for the ball with Chelsea's Joao Pedro during the Champions League soccer match between Chelsea and Paris Saint-Germain in London, England, Tuesday, March 17, 2026. (AP Photo/Kin Cheung)

Chelsea's head coach Liam Rosenior, centre, follows the game during the Champions League soccer match between Chelsea and Paris Saint-Germain in London, England, Tuesday, March 17, 2026. (AP Photo/Kin Cheung)

Chelsea fans display a banner reads "Champions of the World" during the Champions League soccer match between Chelsea and Paris Saint-Germain in London, England, Tuesday, March 17, 2026. (AP Photo/Kin Cheung)