A live-fire demonstration intended to commemorate the 250th anniversary of the U.S. Marine Corps spiraled into chaos on Saturday when an artillery round unexpectedly exploded in the sky above California’s Interstate 5, showering shrapnel onto a patrol car below.

The unsettling incident unfolded near Camp Pendleton in San Diego County during an event graced by the presence of Vice President JD Vance. The demonstration had received authorization from the Trump administration as part of the anniversary celebrations.

As the artillery round detonated prematurely, a California Highway Patrol (CHP) vehicle traveling on the freeway was hit by flying metal debris.

An internal report from CHP revealed that the explosive ordnance detonated prematurely above the freeway, rather than reaching its intended target. This led to damage to a CHP cruiser, which had been positioned nearby to facilitate a temporary traffic hold.

Fortunately, the incident resulted in no injuries. However, it sparked immediate outrage among California officials and intensified ongoing tensions between state and federal authorities. Governor Gavin Newsom criticized the incident as ‘reckless’ and ‘profoundly absurd,’ condemning military exercises that risk civilian safety and infrastructure.

‘This was an unusual and concerning situation,’ said CHP Border Division Chief Tony Coronado, a Marine Corps veteran who oversaw the safety operation. 

‘It is highly uncommon for any live-fire or explosive training activity to occur over an active freeway. As a Marine myself, I have tremendous respect for our military partners, but my foremost responsibility is ensuring the safety of the people of California and the officers who protect them.’

The CHP’s internal report obtained on Sunday, confirmed that metal fragments struck a marked patrol car while officers were supporting a traffic closure along I-5. 

A live-fire demonstration meant to honor the 250th anniversary of the US Marine Corps sent metal shrapnel raining down onto a California Highway Patrol (CHP) vehicle

The incident occurred near Camp Pendleton in San Diego County, during an event attended by Vice President JD Vance 

A map released by the California Highway Patrol show how shrapnel from the demonstration managed to cross over the I-5 interstate

The agency’s statement said officers immediately notified Marine personnel at the scene, who then halted all further firing over the highway.

The report recommends an after-action review to examine how coordination broke down between federal, state, and local agencies – and to tighten protocols before any future military exercises near public roadways.

Camp Pendleton officials later acknowledged that a 155mm artillery round may have exploded outside its designated impact zone during the live-fire portion of the event.

‘We are aware of the report of a possible airborne detonation of a 155mm artillery round outside the designated impact area during the US Marine Corps Amphibious Capabilities Demonstration at Camp Pendleton, CA, Oct. 18,’ said the Marine Expeditionary Force Communication Strategy and Operations team.

‘The demonstration went through a rigorous safety evaluation, and deliberate layers of redundancy, to ensure the safety of fellow citizens. Following established safety protocols, firing was suspended. No injuries occurred, and the demonstration concluded as scheduled.

‘An investigation has been initiated. We are committed to determining the incident’s root cause and applying findings to future missions,’ the statement added.

The mishap immediately reignited criticism from Governor Gavin Newsom, who had already blasted the Trump administration’s decision to authorize live artillery fire over one of California’s busiest freeways.

In a post on X, Newsom wrote that Trump and Vance ‘put lives at risk to put on a show.’

California Governor Gavin Newsom slammed Donald Trump’s plans to fire artillery shells over a the interstate as part of a Saturday’s military demonstration

The beachfront was liked with military vehicles from nearby Camp Pendleton

Artillery units fire as US Army members take part in an amphibious assault demonstration as part of their 250th anniversary celebration attended by Vance

Freeway signs warn drivers on the Interstate of ‘Live Weapons Over Freeway’ in San Diego

‘If you want to honor our troops, open the government and pay them,’ Newsom tweeted.

Just hours before the detonation, Newsom’s office had ordered the 17-mile stretch of Interstate 5 between Los Angeles and San Diego closed, citing safety concerns. 

The move led to massive gridlock across Southern California.

‘Using our military to intimidate people you disagree with isn’t strength – it’s reckless, it’s disrespectful, and it’s beneath the office the president holds,’ Newsom told the New York Times.

The White House and Vice President Vance’s office defended the event as both symbolic and secure.

‘Gavin Newsom wants people to think this exercise is dangerous,’ said William Martin, communications director for Vice President Vance. 

‘The Marine Corps says it’s an established and safe practice. Newsom wants people to think this is an absurd show of force. The Marine Corps says it’s part of routine training at Camp Pendleton.

‘If Gavin Newsom wants to oppose the training exercises that ensure our Armed Forces are the deadliest and most lethal fighting force in the world, then he can go right ahead,’ he added.

Vance told roughly 15,000 Marines that the country would ‘always need [their] warrior spirit,’ and vowed that the administration would ‘make sure you get paid exactly as you deserve’ 

VP Vance arrives to speak at the United States Marine Corps 250th birthday celebration

Vance gives a thumbs up to the audience of Marines during the 250th Amphibious Capabilities Demonstration Beach Bash, at Marine Corps Base Camp Pendleton on Saturday

The artillery fire was part of a round of demonstrations the US military held on Saturday in California to celebrate the Marines’ 250th anniversary 

The closure and explosion left residents furious and local officials blindsided. San Clemente City Councilmember Mark Enmeier said he ‘was not informed’ of the freeway shutdown, calling it ‘completely out of the blue.’

Restaurant owner Joey Abi-Loutfi, whose business sits near an exit ramp, told the Los Angeles Times: ‘What a great use of funding.’

Oceanside Assistant Police Chief John McKean added that even if artillery wasn’t expected to hit traffic, ‘it may frighten drivers when the rounds go off, because it’s going to be going off for about a good 15 or 20 minutes.’

The Federal Aviation Administration also temporarily restricted airspace over the site, while Amtrak’s Pacific Surfliner was briefly halted.

Vance told roughly 15,000 Marines that the country would ‘always need [their] warrior spirit,’ and vowed that the administration would ‘make sure you get paid exactly as you deserve,’ despite what he called the ‘Schumer Shutdown.’