Health chiefs are investigating how a pensioner managed to climb on scaffolding at Ysbyty Glan Clwyd.
A 75 year-old man had to be rescued on Monday evening, after he was spotted scaling the scaffold at the Bodelwyddan hospital, where work on a redevelopment scheme has been taking place. Fire crews managed to help the man climb down.
Management at Glan Clwyd said they were very concerned by what happened and were trying to find out how the man managed to reach the construction area.
An urgent investigation involving contractors and the Betsi Cadwaladr health board is continuing.