Video taken at the underwater site of the sunken Manolis L shows the painstaking task for divers assessing the leaking hull of the ship near Change Islands, in Newfoundland's Notre Dame Bay.
Groups of two make five dives per day. It takes about 10 minutes to reach the hull on the ocean, and divers can only stay down for 30 minutes.
When they reach they surface, they must spend over an hour in a decompression tank.
Divers are drilling, collecting samples and installing plugs on various points along the hull, assessing how much fuel is on board and where it's located.
Representatives from the coast guard, Transport Canada, Environment Canada and several private contractors have established a 200-metre safety zone around the Manolis L to protect divers, and watch for any leaking oil.
The Manolis L has been underwater for over 30 years. A $5-million contract was awarded earlier this summer to the Florida-based company Resolve Marine Group, to dive down to the Manolis L and assess the ship's leaking hull.