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 during a celebration of the 250th anniversary of the Marine Corps, attended by Vice President JD Vance and Defense Secretary Pete Hegseth. Pieces of shrapnel scattered on the closed roadway, striking a CHP patrol car and a motorcycle.
According to a 666-page report dated December 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). The premature detonation is described as beyond reasonable expectations and should not have happened, but it did,” the report states.
Manufactured to a defect tolerance of one in a million, the report ruled out any negligence or wrongdoing by Corps members. However, it remains unclear why the live artillery was fired over a major highway, leading to intense scrutiny from California legislators.
Days after the mishap, 26 California U.S. House members and the state’s two senators sent a letter to Hegseth demanding to know who authorized the live fire and how safety risks were assessed.
The incident has intensified tensions between President Trump and California leaders, including Governor Gavin Newsom, who criticized the unsafe nature of firing live rounds over a busy roadway. Some local leaders expressed frustration over the display, which they believe was orchestrated for political optics at the expense of public safety.
“We’re thankful to the Marines for their thorough 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, stated.
Newsom described the live fire exercise as intended to intimidate opponents during the “No Kings” protests taking place in San Diego on the same day.
“Firing live rounds over a busy highway isn’t just wrong — it’s dangerous,” he remarked.
The demonstration involved aircraft and amphibious assault vehicles, highlighting military capabilities but raising pressing concerns about the appropriateness and safety of such exercises conducted in proximity to populated areas.
An officer reported hearing the sound of pebbles falling on his motorcycle, and others noted striking a Ford patrol vehicle with a piece of shrapnel being recovered from the scene afterward.
The military typically conducts live fire training within designated ranges, making the choice of location for this demonstration particularly unusual and contentious.
