PALM SPRINGS, Calif. (AP) — A U.S. Marine was detained at a California airport after Transportation Security Administration personnel found a live 25 mm explosive round in his checked baggage, police said.

The round was found during the screening process of checked luggage at Palm Springs International Airport on Monday, the Palm Springs Police Department said in a news release.

The Marine told investigators he found the round “in the field” about a year ago and kept it, thinking it wasn’t live.

“Due to extensive rust and corrosion, the round’s original identifying paint markings were no longer visible, making it difficult to determine whether it was an inert training munition or a live explosive device,” police said in the news release.

The Riverside County Sheriff’s Department Explosive Ordnance Disposal Team used X-ray technology to confirm that it was a live round. The team took it to a desert area near Interstate 10, where it was destroyed, the news release said. No one was hurt.

Police said they submitted the case to the Riverside County District Attorney’s Office for a review of potential violations and criminal charges. An email seeking comment was sent to the district attorney’s office Tuesday.

The Marine, who was released to military authorities, could face administrative action by the Marine Corps and a potential civil penalty through the TSA, police said. Emails seeking comment were sent to both organizations.