On Thursday, Sri Lanka navy spokesman Indika de Silva said the efforts to douse the blaze were continuing. Four tug boats and three Sri Lankan and Indian vessels have joined the operation.
The fire erupted May 20 when the ship was anchored about 9.5 nautical miles (18 kilometers) northwest of Colombo and waiting to enter its port.
The Sri Lanka navy believes the fire was caused by chemicals being transported on the Singapore-flagged ship. It was carrying 1,486 containers, including 25 tons of nitric acid and other chemicals that were loaded at the port of Hazira, India, on May 15.