The Metro Explosives Disposal Unit was called to a field along Southwest Clark Hill Road in rural Washington County, southwest of Beaverton, Saturday afternoon for a pipe bomb.
The device was found by 56-year-old Rojelio Alvardo-Nunez who told his employer.
A bomb technician moved the device to a safer location and detonated it. They were not able to determine how much explosive compound was in the device or the type of material.
Sheriff's deputies don't know who placed the device in the field.