A one-kilometre-long oil slick believed to have leaked from a bulk carrier ship is fouling the waters and beaches of Vancouver's scenic English Bay.

It is still not clear what type of type of oil has spilled into the bay, which is surrounded by the city's downtown, the world renowned Stanley Park and numerous popular beaches.

B.C. oil spill

But so far, an estimated 3,000 litres is believed to have seeped from a freighter named Marathassa. The spill was first spotted at 5 p.m. on Wednesday by a local boater.

While clean-up efforts are underway, questions have been raised about the slow emergency response and a lack of information for public officials.

The coast guard says it contracted the Western Canada Marine Response Corporation on Wednesday night to begin to tackle the spill.

A floating barrier has been placed around the carrier ship, and crews are skimming oil off the surface.

B.C. oil spill

Bunker fuel drifts on the surface of Burrard Inlet after leaking from the bulk carrier cargo ship Marathassa, not seen, in Vancouver, B.C., on Thursday April 9, 2015. (Darryl Dyck / THE CANADIAN PRESS)

The coast guard's Capt. Roger Girouard said at a news conference on Thursday that 1,400 litres of oil have already been skimmed from the water.

However, it took the coast guard nearly 24 hours to answer questions regarding the incident.

And officials from the City of Vancouver say it did not find out about the oil slick until 6 a.m. Thursday morning, more than 12 hours after the coast guard first received reports of a spill.

Girouard said that the worst-case scenario is that the slick consists of raw crude oil.

It had originally been recognized as bunker fuel, but officials on Thursday said they couldn't confirm the identity of the oily black substance.

B.C. oil spill

Fuel samples are currently being examined in Transport Canada's labs in Ottawa.

Vancouver city manager Penny Ballem told CTV News Channel that identifying the substance is vital in ensuring that the proper cleanup methods are used.

"The characteristics of it are very important in terms of the health risks, in terms of the recovery effort and … if we get it on the shoreline, what mechanism would be used by the recovery people to clean up," Ballem said.

She added that the Western Canada Marine Response Corporation is responsible for management of the spill on the ocean and on shorelines.

Despite these efforts, some of the oil has ended up along the beaches of the English Bay.

B.C. oil spill

Bunker fuel leaks from the bulk carrier cargo ship Marathassa anchored on Burrard Inlet in Vancouver, B.C., on Thursday April 9, 2015. (Darryl Dyck / THE CANADIAN PRESS)

Commissioner of Vancouver's park, John Coupar, said that workers have been sent to protect people and their pets from the toxic effects of the oil that has washed up on shore.

"We dispatched our rangers right away to walk the beaches, (to) make sure people with dogs are keeping their animals out of the water (and) to ensure the safety of those animals," Coupar told CTV Vancouver.

Peter Ross, director of Ocean Pollution Research Program at the Vancouver Aquarium, says that he found tar balls, as well as oil-coated rocks and barnacles on the beach.

"These animals are very likely to die from acute poisoning," Ross said. "That is very thick oil -- that's problematic."

B.C. oil spill

A seagull walks along English Bay Beach after bunker fuel leaked from the bulk carrier cargo ship Marathassa anchored on Burrard Inlet in Vancouver, B.C., on Thursday April 9, 2015. (Darryl Dyck / THE CANADIAN PRESS)

Ross also said that clean-up efforts have been inadequate and have left the local environment vulnerable.

"Booming and skimming, and trying to recover oil that has escaped (have) a fairly limited effectiveness," Ross said.

"Where (are) your buoys to protect the coastline?"

With a report from CTV Vancouver and files from The Canadian Press