Occupational health and safety officials are investigating an incident involving a diver at the dockyard in downtown St. John's on Thursday.
Emergency personnel were called to the Newdock facility around 12:15 p.m. because a scuba diver was reported as having difficulties.
The Royal Newfoundland Constabulary said when officers arrived on the scene, the man was conscious and that co-workers were lifting him to safety.
He was taken to hospital for treatment.
The RNC said the matter has been turned over to the provincial office of Occupational Health and Safety.
The incident is the second this month to spark an occupational health and safety review. A worker fell two weeks ago while he was working on a ship.