An investigation is being carried out to determine how a fire started at University Hospital Limerick.
The fire broke out at 6.45pm in a plant room located on the roof of one of the hospital laboratories.
The plant room is where all of the electrics for the unit are stored.
The paediatric unit was evacuated as a precaution and 14 children were moved to other areas of the hospital.
The Emergency Department also had to be cleared for a short time, but later re-opened.
All visitors were also asked to leave the hospital.
The fire was later brought under control.