Photo/IllutrationHuo Chuanlin, deputy director of the Department of Ecological and Environment Protection of China's State Oceanic Administration, holds a photo showing a rescue ship and an oil slick during a press conference about the Iranian oil tanker Sanchi, which exploded and sank after a collision in the East China Sea in January, at the Information Office of the Ministry of Transport in Beijing on Feb. 1. (AP Photo)

BEIJING--Chinese officials said Thursday they are still debating whether to try to raise an Iranian oil tanker that sank last month with the loss of all 32 crew members.

Transport ministry officials told reporters that 1,900 tons of the Sanchi's fuel oil and some of the tanker's natural gas condensate cargo remain trapped underwater, complicating plans to salvage the ship.

"We need to consider whether the oil will ignite and explode, or cause other issues," said Zhi Guanglu, deputy head of the China Maritime Search and Rescue Center.

Zhi said China was in communication with Iran, the ship's owners and its country of registration, Panama, "in accordance with international conventions."

China is racing to find ways to extract the underwater oil, which could cause serious environmental damage. The Sanchi sank near important fishing grounds, though officials said seafood from the East China Sea remains safe.

Officials say leaked oil has already contaminated seawater around the site of the wreck. Chinese cleanup crews have been using dispersants and absorbents to clean up oil slicks.

The Sanchi caught fire after colliding with a freighter on Jan. 6 and exploded and sank on Sunday about 530 kilometers (330 miles) southeast of Shanghai.

China has sent a robot submarine to survey the 85,000-ton wreck, which lies under 115 meters (380 feet) of water in the East China Sea.

Three bodies were recovered from the sea and the tanker before it sank. Officials say no other bodies have been found from the crew of 30 Iranians and two Bangladeshis.

The ship's navigation recorder was recovered and the cause of the collision is under investigation.