The Massachusetts State Police Bomb Squad was called to Waltham on Monday after contractors dug up what appeared to be old military ordnance, the State Fire Marshal's Office confirmed.
Officials said the contractors were working on Foundry Avenue when they made the find and called in the Waltham Fire Department. The bomb squad responded to assess the items and to safely remove and dispose of them.
The Massachusetts Department of Fire Services later confirmed that 13 cannonballs of various sizes were removed.
The ordinance was brought to a safe location and countercharged, the department said.
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No injuries were reported.
A state hazmat team was also initially called in but determined there were no environmental hazards. They have since cleared the scene.
