An environmental disaster may have been avoided, but a landmark has been lost in the waters of Howe Sound near the community of Britannia Beach, north of Vancouver.

The vessel, once known as the Seaspan Chinook, has been a fixture docked in Britannia Beach for five years, but last night the boat began to sink, spilling 500 litres of oil lube and diesel fuel.

The tugboat can hold up to 55,000 gallons of fuel. But luckily, the tanks were almost empty when the vessel was pulled from service.

"No one was aboard the vessel when it sank," said Dan Bate, a spokesperson for the Coast Guard.

"It is believed the tanks onboard were largely empty; however, there are several quarts of diesel sheen in Howe Sound."

B.C. Ministry of Environment spokesperson Kate Thompson said government officials are working to determine how much more diesel is inside the heritage vessel.

"If it is diesel, it dissipates very, very quickly, especially in sunlight."

RCMP spokesperson Cpl. Dave Ritchie said the cause of the sinking is unknown.

"We don't know anything, other than there is some fuel spill on the rocks around the area," he said.

For people like Gerhard Rietel, who drive by Britannia Beach on the Sea to Sky Highway almost daily, the Chinook was part of the scenery.

He calls the sinking mind boggling and disappointing.

"I noticed it instantly," he told CTV News. "There was something missing, you know, it's like a mountain's gone all of a sudden."

Once the cleanup is complete, the vessel may be salvaged, something Britannia Beach local Horst Wolter does not want to see.

"(Boats) are just a disaster," he said. "They're dirty. They're junk."

The vessel is believed to be owned by the Maritime Heritage Society of Vancouver.

It is the responsibility of the owners to pay for area's cleaning, Bates said, noting that the Coast Guard is onsite monitoring the situation and is involved with the clean up.

The Ministry of Oceans is confident the leak is under control.

With a report from CTV British Columbia's St John Alexander