Fuel oil from a Philippine tanker that sank amid bad weather in Manila Bay on Thursday has begun leaking from the vessel, the coast guard said on Saturday.

A coast guard spokesman said divers had discovered a "minimal leak" from the ship's valves, but said it was "not alarming yet." 

Previously, the coast guard had said leaking oil appeared to be only the diesel fuel used to power the vessel. 

The sinking of the MT Terra Nova, which is carrying some 1.4 million liters (ca. 370,000 gallons) of industrial fuel oil, has the potential to become the worst oil spill disaster in the country history. The capital Manila and surrounding shoreline are considered at risk.

The tanker is currently on the sea bed, some 34 meters (116 feet) under water. 

One crewmember died and 16 were rescued after the vessel capsized and sunk on Thursday . 

What do we know?

The spokesman, Rear Admiral Armando Balilo, said there was only a "small volume" of oil emanating from the ship.

"We're hoping that tomorrow we will be able to start siphoning the oil from the motor tanker," he said, adding that a vessel had been sent to the area to carry the recovered oil.

He called for a temporary halt to fishing in the waterway, which thousands of fishers and tourism operators rely on for their livelihoods.

The oil slick has reportedly more than tripled in size from Thursday, reaching an estimated length of 12-14 kilometres (7.5-8.7 miles) across the bay.

Poor spill record for Philippines

The Philippines has suffered a number of oil catastrophes in recent years.

In 2023, a tanker with 800,000 liters of industrial fuel oil on board sank off the central island of Mindoro, with the resulting contamination devastating the fishing and tourism industries for months.

Another tanker sank off the central island of Guimaras in 2006, causing a massive oil spill  that destroyed a marine reserve and ruined local fishing grounds.

tj/dj (AFP, AP)