It has emerged that safety concerns had been previously expressed about the 'tower block' at Altnagelvin Hospital which was last night the scene of a fire.
It is understood that a fire on the top floor resulted in water tanks collapsing - this lead to 120 patients being evacuated from the top floor to floor 3.
It took up to 50 firefighters and other personal to bring the situation under control.
During that process, hospitals throughout Northern Ireland and Letterkenny General Hospital were informed and stood ready to receive patients if necessary.
There were no injuries.
Much of Altnagelvin has undergone a modernisation - but this is the second fire in the tower block in recent times.
Foyle MLA Pat Ramsey says it must now be inspected to ensure its safe for patients: