The incident happened aboard the ferry MV Beaumont Hamel, which was in dry dock at the time undergoing work.
Police and firefighters responded to reports of an unresponsive man onboard the Beaumont Hamel at 12:50 p.m.
The RNC says four men have been taken to hospital and the area has been secured and the area was evacuated as a precaution. Occupational Health and Safety officials with Service NL are investigating.
More details will be provided as they become available.