AUTHORITIES IN SRI Lanka are trying to head off a potential environmental disaster as a fire-damaged container ship that had been carrying chemicals sinks off the country’s main port.

The MV X-Press Pearl started sinking on Wednesday, a day after authorities extinguished a fire that had raged on the vessel for 12 days.

Efforts to tow the ship into deeper waters away from the port in Colombo failed after the ship’s stern became submerged and rested on the seabed.

The Singapore-flagged ship’s operators, X-Press Feeders, said the fire destroyed most of the ship’s cargo, which included 25 tons of nitric acid and other chemicals, but there are fears that remaining chemicals and hundreds of tons of oil from the fuel tanks could leak into the sea.

Such a disaster could devastate marine life and further pollute the island nation’s famed beaches. The disaster has already caused debris — including several tons of plastic pellets used to make plastic bags — to wash ashore.

The government has already banned fishing along about 50 miles of coastline.

The ship’s operator said on Thursday that the ship’s stern was resting on the seabed about 70ft below the surface and the bow was “settling down slowly”. The company said salvage experts were with the vessel “to monitor the ship’s condition and oil pollution”.

The company said its experts are co-ordinating with Sri Lanka’s navy to deal with an oil spill or other pollution.

The navy and coastguard are preparing for an oil spill with assistance from neighbouring India. India has sent three ships to help, including one equipped to deal with marine pollution.

Environmentalist Ajantha Perera said there was the potential for “a terrible environmental disaster” as hazardous goods, chemicals and oil could be released into the water and destroy marine ecological systems.

Charitha Pattiaratchi, a professor of oceanography at the University of Western Australia, said as many as three billion tiny plastic pellets had already been released into the sea and were washing up on beaches. He said the pellets “will persist in the marine environment forever as they are not biodegradable”.

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 port.

The navy believes the blaze was caused by the vessel’s chemical cargo, which was loaded at Hazira, India, on May 15.

Sri Lankan police are investigating, and a court in Colombo on Tuesday banned the captain, engineer and assistant engineer from leaving the country. The government has said it will take legal action against the owners of the ship to claim compensation.

Sri Lanka’s environment minister Mahinda Amaraweera said: “It wouldn’t be an easy task to calculate the damage caused to our environment.

“If this disaster happened due to negligence, then those responsible should be punished.”