A vintage sail boat at the bottom of the North West Arm could be leaking oil or fuel into the water.
On Friday an oily sheen could be seen floating on the water near the boat, reported the CBC's Rob Gordon.
With just a portion of the mast jutting out of the water near the Armdale Rotary in Halifax, the sunken yacht has attracted onlookers, but so far no one knows how the boat sank.
"It's a shame," said Leslie Spears, a resident in the area.
"It was a nice old boat, it was wooden classic. It was there for about three years. I guess nobody took care of it."
Both the Halifax Port Authority and the Coast Guard have inspected the site. A buoy marks the wreck to warn other boaters.
The boat's owner, a local TV producer named Josh Hannigan, could not be reached for comment.
If he doesn't deal with the wreck himself the port will have to take over and either remove the boat, or set up permanent markers.