Marine Corps Investigates Live-Fire Shell Detonation Over California I-5

On October 18, 2025, during the U.S. Marine Corps' 250th anniversary celebration at Camp Pendleton, a 155mm artillery shell prematurely detonated over Interstate 5, scattering metal shrapnel onto the freeway and striking California Highway Patrol (CHP) vehicles stationed for traffic control. The mishap occurred during a live-fire demonstration attended by Vice President JD Vance and Defense Secretary Pete Hegseth, leading to the immediate suspension of all live ordnance firing over the freeway. Although no injuries were reported, the incident caused visible damage to a CHP patrol vehicle and a motorcycle, raising safety concerns and prompting a comprehensive investigation by the Marine Corps. Governor Gavin Newsom criticized the Trump administration for the event, calling it a "reckless" display of force, while CHP officials emphasized the need for improved coordination among federal, state, and local agencies during such exercises. An internal CHP report recommended an after-action review to strengthen communication and safety procedures for future live-fire demonstrations near civilian infrastructure. The freeway was reopened after safety sweeps confirmed no additional hazards, and Camp Pendleton authorities continue to investigate the cause of the premature detonation.