An apartment complex in Middlesex County was evacuated Thursday afternoon after suspected bomb-making materials were found inside a truck.

Old Bridge police say that a maintenance worker found the materials in a truck on London Terrace in the Parlin section of town.

Authorities say that the vehicle had been parked there for over 30 days and maintenance crews were going to tow it away when they opened the trunk and found the device in the back. Police say that the device was the size of a baseball and was covered in nails and ball bearings.

Residents were evacuated as a precaution.

“The maintenance guy came banging on the door telling me to get out, there’s a bomb threat in my building,” says resident James Billups. “I got my keys and exited immediately.”

Police say that officers removed the device by hand and say that it wasn’t loaded with any explosive material. State police forensic experts are expected to examine the device.

Tenants were allowed back inside the building about three hours later.

Old Bridge police say that investigators know the name of the person who owns the vehicle and are looking into the situation.