The Singapore-registered MV X-Press Pearl, carrying 1,486 containers, including 25 tonnes of nitric acid along with other chemicals and cosmetics, was anchored offshore when a fire erupted after an explosion on May 20.
Flaming containers filled with billions of plastic pellets tumbled into the sea from the ship's deck as emergency crews sought to contain the blaze over the next two weeks.
The pellets have already fouled surrounding beaches and fishing grounds, forcing the government to ban fishing along an 80-kilometer stretch of coast.
The ship, which was only four months old, began to sink early on Wednesday (June 2). A salvage crew tried to tow the vessel to deeper water, away from the coast, but the attempt was abandoned after the rear of the ship touched the sea bed.
The ship's operators, X-Press Feeders, said on Friday there was no sign of an oil spill.
Sri Lanka's government has said it would seek redress for the incident, while Singapore has started its own investigation into the incident.