Live Artillery Shell From Camp Pendleton Detonates Over Interstate 5, Hits CHP Vehicle

On Saturday, October 18, 2025, an exercise held by the United States Marine Corps (USMC) at Camp Pendleton resulted in a dangerous incident: a 155-mm artillery round detonated prematurely over a section of Interstate 5 in San Diego County, and metal fragments struck a vehicle belonging to the California Highway Patrol (CHP)What Happened

The Marine Corps had scheduled a large-scale demonstration as part of its 250th-anniversary observance, to be held at Camp Pendleton. The exercise included live-fire artillery rounds, amphibious operations, and a demonstration of naval and Marine capabilities.

To accommodate the event, the CHP closed a 17-mile stretch of I-5 between Harbor Drive (Oceanside) and Basilone Road (San Onofre) from approximately 11 a.m. to 3 p.m. on Saturday.

At around 1:45 p.m., during the live-fire portion of the event, a 155 mm artillery round reportedly detonated above the freeway—outside the designated impact zone—causing shrapnel to fall down. One CHP patrol vehicle, parked at a traffic break supporting the closure, was struck by a 2-inch-by-0.5-inch (5 cm × 1.3 cm) piece of metal that left a dent and scratch on the hood. A nearby motorcycle registered a similar incident: the rider heard “pebbles” landing around him and found a 1-inch-by-0.5-inch piece of shrapnel near his bike. No injuries were reported.

In response, the Marine Corps suspended further firing of live ordnance over the freeway, and an investigation was launched to determine the root cause.

Safety & Procedural Concerns

• The CHP noted that “it is highly uncommon for any live-fire or explosive training activity to occur over an active freeway.” Border Division Chief Tony Coronado commented that while he holds the military in high regard, his priority is the safety of California citizens and officers.

The internal report by the CHP recommended an after-action review focusing on planning, communication and coordination between federal, state and local agencies when training activities occur near public infrastructure.

Reactions & Political Dimension

Governor Gavin Newsom publicly criticized the exercise, labeling it a “vanity project” and accusing federal officials of putting people’s lives at risk for spectacle. He asserted the state’s duty is to safeguard travelers and residents, not accommodate military demonstrations that cross over civilian transit routes.

Meanwhile, the Marine Corps maintained that the exercise had undergone rigorous safety evaluation and multiple layers of redundancy, underscoring that no injuries occurred and the event proceeded as scheduled once the incident was handled.

Impact and Considerations

• The I-5 corridor in that region is vital: thousands of commuters, commercial freight, and rail services traverse it daily. The closure of the freeway and a parallel rail line for the event caused significant disruptions.
• Although this particular event caused no injuries, the incident raises questions about using major public infrastructure as a backdrop for live-fire military training or demonstrations.
• Future planning of such events may require tighter safety buffers, more advance public notice, and less dependence on closing or placing live ordnance over active transportation routes.

What’s Next