An oil tanker loaded with two million barrels of Kuwati crude sailing toward India's Paradip refinery caught fire Thursday morning off Sri Lanka's coast, raising concerns about an oil spill.

The fire in the engine room of New Diamond, a very large crude carrier, was caused by an explosion, said Sri Lanka Navy spokesman Indika de Silva.

The fire spread to other parts of the vessel, according to Sri Lanka Navy. Parts of the blaze have since been doused, the Indian Coast Guard said in a Twitter post on Friday. A crack of about 2 meters has been seen 10 meters above the waterline in the rear of the tanker's port side, it added.

Concerted joint #SAR & #FireFighting efforts by ICG Ships, SL Navy & tugs resulted in rescue of 22 out of 23 crew safely. Search for 01 missing crew (Filipino) in progress. No oil spill reported in area. 02 Emergency Towing Vessels being deployed by GoI for #MTNewDiamond. pic.twitter.com/bjqMsQkio9

— Indian Coast Guard (@IndiaCoastGuard) September 4, 2020

While, there have been no reports of large-scale oil leakage, Sri Lankan authorities are deploying equipment to prevent pollution. The area is south of a belt well known for whale sightings, and any oil spill could threaten marine life in the region.

New Diamond was about 65 kilometers (40 miles) off the east coast of Sri Lanka when it caught fire, according to ship-tracking data compiled by Bloomberg. The cargo was loaded at Mina al Ahmadi on Aug. 23 and scheduled to arrive at Paradip on Sept. 5.

The tanker has drifted closer and was positioned about 24 nautical miles from the Sri Lankan coast at 5:30 a.m local time, said Dharshani Lahandapura, chairperson of Sri Lanka's Marine Environment Protection Authority. "We are analyzing the situation. It will be huge disaster if the spill occurs."

All but one of the 23 New Diamond crew, from Greece and the Philippines, have been rescued, while one person is missing, presumed dead, de Silva said.

The vessel was chartered by Indian Oil Corp., a spokesman for India's biggest state refiner said. Indian Oil operates a 15-million-ton-a-year oil refinery at Paradip in India's eastern state of Odisha.

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