A rusty bomb covered in debris washed up on a California shore days after heavy surf pounded the coastline.

On New Year’s Eve, the Santa Cruz County sheriff’s bomb squad headed out to inspect the bomb at Pajaro Dunes, located between Santa Cruz and Monterey.

After an x-ray scan and visual inspection, authorities determined the device was an inert military ordnance – an item with no explosive materials, the sheriff’s office said on social media.

Once the bomb squad deemed the item safe, they called in personnel from the Travis Air Force Base to remove and transport the inert device, according to the sheriff’s office.

The device was later determined to be a US World War II-era Navy practice bomb, according to a statement from Travis Air Force Base, and it will remain with the base’s explosive ordnance disposal.