Local historians were stumped as to how a “military object” could have found its way to the industrial area of South San Francisco.
Despite the area’s history with shipbuilding during both World Wars, the discovery of possible ordnance 20-30 feet beneath the surface seemed improbable, San Mateo County Historian Mitch Postel said.
The old Tanforan horseracing track in San Bruno — where the mall now stands — was used as an ammunitions dump during World War II, but that was miles away from the Oyster Point Boulevard site where the object was found, Postel said.
On Saturday, construction crews at 333 Oyster Point Blvd. unearthed a military object between 4- and 5-foot-long and called the San Mateo County Bomb Squad. The object was ultimately removed and taken for further study by the U.S. Army’s Explosives Ordnance Disposal Unit.
The site was evacuated and the road closed to all traffic until the object was removed.
The site, formerly a U.S. Steel plant, has large amounts of slag, a byproduct of steel production, that needs excavation before construction can begin on Slough Estates’ 315,444-square-feet research and development facility with underground parking.
The industrial area was used heavily during wartime for shipbuilding, Postel said.
South San Francisco fire officials said the object was torpedo-like in shape.
It was not detonated, but was removed safely to Moffett Airfield for further testing.
The sergeant onsite suspected the object to be a sort of training device, according to a Slough Estates statement. It’s unknown whether the object had any explosives in it.