A Marine Atlantic worker says he is not confident that the Crown corporation has done all it can to protect workers from asbestos.

Phonse Griffiths, a maintenance worker aboard the container ship Atlantic Freighter, said he was alarmed when the company posted signs around the vessel a month ago, warning workers of asbestos.

"I requested a transfer to another vessel and that request was denied by Marine Atlantic," said Griffiths, a 28-year veteran of the ferry company who has worked on the freighter for six years.

"Now I'm being forced back to work in what I believe are unsafe work conditions."

Griffiths said he wants to know how long Marine Atlantic — which operates ferries running between Nova Scotia and southern Newfoundland — has known about the asbestos.

Griffiths, who lives in Ship Harbour, Placentia Bay, said he is worried about exposure levels to materials that he did not know involved asbestos.

Marine Atlantic officials were not available for an interview. An official said air quality tests have been done and that the company can assure the crew that they are working in a safe environment.