Sri Lankan authorities have taken water samples to try to determine whether a fire-ravaged cargo ship slowly sinking off the coast is leaking oil, officials said.

Results of the tests taken on Thursday by the Sri Lankan Marine Environment Protection Authority are still pending, the country’s environment minister added.

The tests were prompted by satellite images from Planet Labs which showed a substance that could be oil in the water near the Singapore-flagged MV X-Press Pearl, which was devastated by a fire over 12 days before it started sinking last week.

Plastic pellets
Plastic pellets washed ashore from the container ship has been collected by the naval officers and kept in sacks on the beach at Kapungoda (AP)

The fire destroyed most of the ship’s cargo, which included 25 tonnes of nitric acid and other chemicals.

However, debris including burned fibreglass and tonnes of plastic pellets have already polluted nearby beaches and there are concerns that a spill of remaining chemicals and oil on the ship could devastate marine life.

The ship’s operator X-Press Feeders said that “a grey sheen has been observed emanating from the vessel, and water samples are currently being tested”.

Nalaka Godahewa, state minister in charge of coast conservation, said in a tweet that the satellite imagery “could be misleading” and that both the Sri Lankan and Indian navy had confirmed to him that there was no large oil spill.

Plastic pellets
A crab roams on a beach polluted with polythene pellets from the MV X-Press Pearl (AP)

The fire erupted on May 20 when the ship was anchored about 9.5 nautical miles north-west of Colombo and waiting to enter the Sri Lanka’s main port.

The navy believes the blaze was caused by its chemical cargo.

The fire burned for 12 days before being extinguished last week. The vessel then started sinking and attempts to tow it into deeper waters failed when the stern sank to the seabed.

The vessel remains partly submerged in waters about 70ft deep.

A Colombo court has banned the ship’s captain, chief engineer and assistant engineer from leaving the country.

The government has said it will take legal action against the owners of the ship to obtain compensation.