During a weekend military exercise at a U.S. Marine Corps base, metal fragments from an artillery shell explosion struck and damaged a California Highway Patrol vehicle. This incident unfolded as live rounds were fired over a highway, despite Governor Gavin Newsom’s objections. The exercises, observed by Vice President JD Vance, fortunately resulted in no injuries, according to state officials on Sunday.

The mishap took place on Saturday at Camp Pendleton when the ordnance unexpectedly exploded overhead, as detailed in a news release by the California Highway Patrol.

Governor Newsom had voiced strong opposition to the use of live munitions over Interstate 5, citing safety concerns. In response, a 17-mile segment of the highway, which connects Los Angeles and San Diego, was temporarily closed for the drills. These exercises were part of the preparations for the Marine Corps’ upcoming 250th anniversary celebration.

The event transpired within an area where traffic had been halted by officers, the highway patrol noted.

A spokesperson for the Marine Corps acknowledged awareness of “a possible airborne detonation” involving a 155 mm artillery round outside the intended impact zone set for the exercise.

“Following established safety protocols, firing was suspended. No injuries occurred and the demonstration concluded as scheduled,” Capt. Gregory Dreibelbis of the I Marine Expeditionary Force said in an emailed statement.

An investigation has been initiated, he said.

“We are committed to determining the incident’s root cause and applying findings to future missions,” Dreibelbis said.

The Marine Corps had said there was nothing unsafe about the exercise and that it was unnecessary to disrupt traffic on I-5.

An incident report filed by the highway patrol said one officer heard what sounded like pebbles falling on his motorcycle and about 3 feet (91 centimeters) around him. His motorcycle was not damaged. He found a 1 inch-by-0.5 inch (2.5 cm-by-1.3 cm) piece of shrapnel nearby.

One unoccupied patrol vehicle was hit by shrapnel. Officers found a 2 inch-by-0.5 inch (5 cm-by-1.3 cm) piece of shrapnel on the vehicle. It left a small dent and scratch on the vehicle’s hood.

Officers said they notified the Marine Corps, which then canceled the firing of additional live ordnance over the freeway. Officers didn’t find any additional metal on freeway lanes and reopened the road.

Newsom, a Democrat, posted a comment on the social media site X Sunday.

“We love our Marines and owe a debt of gratitude to Camp Pendleton, but next time, the Vice President and the White House shouldn’t be so reckless with people’s lives for their vanity projects,” Newsom said.

Vance, a Republican, and Defense Secretary Pete Hegseth visited the base in north San Diego County for the Nov. 10 anniversary of the Marine Corps’ founding and to watch troops demonstrate a beach assault. Vance spent four years in the Marines and served a tour in Iraq.