The Defence Forces bomb squad was called to dispose of a grenade, believed to be from the War of Independence, in Ballsbridge on Monday morning.
The Mills 36 hand grenade was discovered by staff carrying out maintenance work on a bridge at Pembroke Road near the American Embassy in Dublin 4.
The army bomb disposal team arrived on the scene just after 11am, where they carried out an initial assessment of the area.
A cordon was put in place for the duration of the operation to ensure public safety. The team then carried out a controlled explosion and the grenade was disposed of. The scene was declared safe at 12.45pm.
According to the Defence Forces, Mills 36 hand grenades were regularly used throughout the War of Independence and the second World War. They were patented and developed by the British Army in 1915 and continued to be manufactured up until the 1980s.
A statement from the Defence Forces said: “Historic munitions from conflicts in the early 20th century can be encountered from time to time.
"Should members of the public find such munitions they are advised to maintain a safe distance, inform An Garda Síochána, who in turn will request Defence Forces assistance."
