MANILA – A motor tanker loaded with 800,000 litres of industrial oil sank on Tuesday, spilling its diesel fuel off the coast of Naujan town in Oriental Mindoro, an island province about 207km to the south of the capital Manila.

The Philippine Coast Guard (PCG) said as of 6am on Wednesday, the diesel that powered the MT Princess Empress had left a spill spanning at least 6km long and 4km wide in the surrounding waters, with the vessel completely submerged.

The ship is operated by RDC Reield Marine Services.

It is not known if the ship’s industrial oil cargo was also spilled. The PCG’s marine environmental protection group is continuing to assess the area.

The PCG plans to install booms, or plastic barriers, to help contain the diesel spillage.

An agent of MT Princess Empress told the coast guard that it will send two tugboats to monitor the ship and install its own booms.

According to the PCG, the MT Princess Empress departed from the Bataan province in the country’s south-west coast, and was headed to Iloilo, an island province in central Philippines.

The tanker encountered engine trouble due to overheating, and then drifted towards the waters near Oriental Mindoro before rough sea conditions inundated the ship.

The PCG said a foreign-flagged vessel rescued all 20 crew members, who were deemed to be in good physical condition after a check-up at a hospital in Naujan town.

Mayor Jennifer Mindanao-Cruz of Pola, a coastal municipality beside Naujan known for its white-sand beaches, ordered residents and town officials to prepare in case the diesel spill reaches the area.

She posted on Facebook images of several life jackets, rafts and other life-saving devices she believes came from the submerged oil tanker.