The army bomb disposal team was called in to the Royal College of Surgeons this afternoon to deal with an unstable chemical.
The college said an internal audit of its chemical lab found that an unstable chemical had degraded and gardaí and the army were notified.
The army Explosive Ordnance Disposal Unit arrived at around 12.30pm.
After an examination, the chemical was deemed too unstable to transport and a controlled explosion was carried out on nearby waste ground.
York Street, St Stephen's Green West and Mercer Street were all closed for a time and traffic was diverted via Dawson Street.
Traffic has since returned to normal in the area.
