A stricken Iranian oil tanker continued to burn out of control for a third day in the East China Sea as rescue boats struggled Tuesday to locate missing sailors before the vessel explodes.

The tanker Sanchi, run by Iran’s top oil shipping operator, has been on fire since late Saturday night, when it hit a freight ship about 160 miles off the coast of Shanghai, burst into flames and began spilling oil into the sea.

“We can’t grasp the level of oil contamination at this moment," Park Sung-dong, an official from South Korea’s Ministry of Oceans and Fisheries, told Reuters. "The cargo is still on fire, so it is hard to figure out if oil is being spilled."

Dozens of rescue boats that have responded to the scene are facing wind-driven rain and waves as high as 10 feet, China's Ministry of Transport said Tuesday in a statement. The poor weather conditions, fierce flames and threat of poisonous gases have kept crews away from the stricken vessel under fears it may also explode.

Two South Korean officials told Reuters the flames are keeping the South Korean Coast Guard’s search and rescue team as far as three miles away from the tanker. Chinese state broadcaster China Central Television showed video Monday of boats trying to douse the flames with water, and reported the boat could still explode.

The tanker was carrying nearly 1 million barrels of condensate, a type of gassy, ultra-light oil, when it collided with the Hong Kong-registered freighter CF Crystal, which was carrying grain from the United States. All 21 crew members of the Crystal were rescued, the Chinese ministry said. The Crystal's crew members were all Chinese nationals.

IRANIAN OIL TANKER BURNING OFF CHINA MAY EXPLODE, BODY FOUND IN SEARCH FOR MISSING CREW

A sailor on the fishing boat that rescued the crew of the CF Crystal told the state-owned Xinhua News the blaze on the oil tanker kept "exploding like bombs.

“The fire was so fierce. It kept exploding like bombs. So loud,” Zhu Tingwen said.

For the crew on board the Sanchi, the situation becomes more grim as the days go on.

Rescuers found a body on Monday believed to be of a sailor from the oil tanker, China's Ministry of Transportation said, as the search continued for another 31 missing from the same ship.

The ministry said the body recovered Monday had yet to be identified but was wearing a protective suit designed to withstand cold seawater. There was no further word about the others missing.

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It wasn't immediately clear what caused the collision, which happened in open seas rather than a narrow channel where such accidents are more common.

The collision has set off concerns of a potential environmental disaster, although condensate is more likely to evaporate or burn off immediately than thick, heavy crude oil. However, the Sanchi's own fuel that leaked during the collision will be more difficult to clean, especially if the tanker explodes and sinks.

An official in Iran's Oil Ministry, who spoke to The Associated Press on condition of anonymity because he was not authorized to speak to reporters, said the tanker was owned by the National Iranian Tanker Co. and confirmed that 30 of the tanker's 32 crew members were Iranians. The others are Bangladeshi.

It's the second collision for a ship from the National Iranian Tanker Co. in less than a year and a half. In August 2016, one of its tankers collided with a Swiss container ship in crowded waters near Singapore, damaging both ships but causing no injuries or oil spill.

The Associated Press contributed to this report.