Military report cites 'one in a million' malfunction for shrapnel rain on California highway

Live fire demonstration at Camp Pendleton led to artillery shell detonating over I-5, striking CHP vehicles

Mar. 18, 2026 at 1:18am

Got story updates? Submit your updates here. ›

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. The report concluded there was 'no definitive answer' for why an artillery shell exploded early at an altitude of about 1,480 feet, but ruled out negligence or wrongdoing by Corps members.

Why it matters

The incident deepened conflicts between the Trump administration and California leaders, with some Republicans initially criticizing the governor for closing a 17-mile stretch of the freeway ahead of the live fire exercise, while others saw it as a dangerous and unorthodox military display orchestrated for the benefit of Trump administration officials.

The details

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 and struck a CHP patrol car and a motorcycle. The Marines concluded that there 'is no definitive answer' to why the M795 high explosive round detonated early, but said such a premature detonation is 'beyond reasonable expectations and should not have happened'.

  • The incident occurred on October 18, 2026 during a live fire demonstration at Camp Pendleton.
  • The Marine Corps report was dated December 19, 2026 and first reported on March 18, 2026.

The players

JD Vance

Vice President of the United States.

Pete Hegseth

U.S. Secretary of Defense.

Gavin Newsom

Governor of California.

Eric Smith

Commandant of the U.S. Marine Corps.

Garrett 'Rainman' Hoffman

Brigadier General in the White House Military Office.

Got photos? Submit your photos here. ›

What they’re saying

“Firing live rounds over a busy highway isn't just wrong — it's dangerous.”

— Gavin Newsom, Governor of California

“It will be a good show regardless of who shows up.”

— Eric Smith, Commandant of the U.S. Marine Corps

“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, Spokesperson for Governor Newsom's office

What’s next

The Marine Corps report did not specify any next steps, as the investigation concluded the malfunction was a 'one in a million' event that could not have been prevented.

The takeaway

This incident highlights the risks and challenges of conducting live fire military demonstrations in populated areas, and the potential for such events to become politically charged, especially in an era of heightened tensions between state and federal officials.