UPDATE: 4 p.m.
Explosive Ordinance Disposal experts deployed from the Boise Police Department and Mountain Home Air Force determined late Tuesday afternoon that a 155 millimeter artillery round discovered in the backyard of a vacant home on Sonora Avenue is "an expended illumination round and poses no danger."
Law enforcement said the round would be taken from the scene and disposed of.
Ada County Sheriffs Deputies have opened up surrounding roads and have begun allowing neighbors to return to their homes.
ORIGINAL POST 2:30 p.m.
Ada County Sheriffs Deputies have set up a safety perimeter around a home in South Ada County where a decades-old 155 millimeter artillery round was discovered Tuesday afternoon.
The property owner told law enforcement that the round was found in the backyard of a recently-vacated rental property on the 12700 block of Sonora Avenue. As a precaution, deputies are treating the round as "live" ammunition and have called in emergency personnel from Boise Police and Mountain Home Air Force Base to assist.