A cargo vessel carrying tonnes of chemicals is sinking off Sri Lanka’s west coast, the country’s government and navy reported on Wednesday, in one of Sri Lanka’s biggest marine catastrophes.

The Singapore-registered MV X-Press Pearl, carrying 1,486 containers, including 25 tonnes of nitric acid, along with other cosmetics and chemicals, was anchored off the island’s west coast when a blaze broke out on May 20.

Authorities have been trying to put out the fire since then, as flaming containers laden with chemicals have fallen from the ship’s deck, the navy reported last month.

Tonnes of plastic pellets have swamped the island’s coastline and rich fishing grounds, leading to one of the worst environmental crises in decades, according to experts.

Fisheries minister Kanchana Wijesekera said in a tweet that “the salvage company involved in the X-Press Pearl has indicated that the vessel is sinking at the current position.”

The government has prohibited fishing along an 80-kilometre stretch of coastline, affecting 5,600 fishing boats, while hundreds of soldiers have been deployed to clean the beach.

Wijesekera added that a salvage crew is towing the ship to deeper water.