A plane taking off at San Diego International Airport in 2020
Construction workers at the San Diego International Airport's Terminal 1 dug up a grenade Thursday, prompting a response from law enforcement.
The grenade was old and inert, meaning it had been hollowed out as a training tool and did not have the potential to explode, according to airport officials.
When the grenade was discovered at about 12:10 p.m., the airport called Harbor Police officers and K-9 units to investigate. San Diego Fire-Rescue's Metro-Arson Strike Team was also called in and ultimately took possession of the grenade.
The construction area was cleared but operations at the airport continued largely as usual. Only one traffic lane to Terminal 1 was affected, officials said.
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It was not immediately clear what would become of the grenade -- or where it came from in the first place.
During World War II, the San Diego airport was operated by the U.S. Army Air Corps and had a runway used by long-range bombers, according to the airport authority.
"The 8,750-foot 'mega-runway' built to accommodate World War II-era long-range bombers made San Diego International Airport 'jet-ready' long before United Airlines became the first airline to offer pure jet service in September 1960," a post on their website read.
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Terminal 1 has been under construction for three years to add 30 new gates to the airport. The project also includes a new parking plaza with an additional 2,800 spots.
