A fishing boat berths in seawater polluted by crude oil in Dalian's Xingang Harbor Monday.Photo: CFP

By Deng Jingyin in Dalian and Chen Rui in Beijing

The threat to international waters from the oil spill triggered by pipeline explosions in the northeastern port city of Dalian has been greatly reduced as strong winds changed direction and cleanup work accelerates with oil-eating bacteria used for the first time.

Experts warned that frequent oil spills have been posing a great threat to the coastal ecological environment in China, whose oil trade mainly depends on shipping from abroad.

Two crude pipelines exploded Friday evening in Xingang Port in Dalian, Liaoning Province. The blasts caused an oil slick that stretched for 183 square kilometers off the Dalian coast. Although booms are being used to prevent the spill from spreading, workers are concerned the situation may worsen if winds change direction or if there is rainfall.

Officials from the Liaoning Maritime Safety Administration (MSA) said Tuesday that much of the spilled oil has been blown toward the coast since the wind direction changed Monday, which may have a negative environmental impact close to the city but is good for the general cleanup and lowers the risk of polluting the open sea.

Maritime agencies have set up 40 monitoring stations to supervise a 1,500-square-kilometer area off the city's coast, with 40 specialized oil-spill-control vessels and about 800 fishing boats rushing to mop up the oil slick..

"Our priority is to collect the spilled oil within five days to reduce the possibility of contaminating international waters," Dai Yulin, vice mayor of Dalian, said Tuesday.

Over 23 tons of oil-eating bacteria have been used to clean up the oil, the Xinhua News Agency reported. The use of the oil-eating bacteria at the Dalian spill is the first time China has made major use of biotechnology to solve an environmental pollution problem.

Wu Jin, a doctor at the Institute of Microbiology at the Chinese Academy of Sciences, said oil-eating bacteria, unlike chemical oil-dispersants, can work 24 hours a day and is more environmentally friendly.

Li Yingjun, chief of the supervision department of Dalian MSA, told hexun.com, a financial news portal, that the cleaning vessels worked 14 hours per day and that 17 square kilometers of seriously polluted seawaters have been almost completely cleaned up. The focus is now turning toward the less-polluted area.

Liaoning MSA reported that the port of Dalian fully reopened to traffic as of 5 pm Tuesday as waterways affected by the oil slick were cleared for the resumption of shipping.

But local officials said oil shipments from Dalian, which lies at the heart of northeast China's crude-oil production base and is the country's vital oil trans-shipment destination, would not be immediately restored.

Local petroleum companies' tankers have reduced oil shipments from Dalian to southern Chinese provinces, while refineries are slowing operations following the blasts.

The oil tank area of Xingang Harbor was still blocked off Tuesday, with all requests for visits refused.

The Bureau of Fisheries, affiliated with the Department of Agriculture, said Tuesday that the oil spill in Xingang port hasn't had an obvious impact.

But if the polluted area expands, it may have an impact on aquaculture, the bureau warned.

An insider at the fishery department of the Ministry of Agriculture told the Global Times that the oil slick is only about 68 kilometers from Guanglu Island, a main source of seafood in Dalian.

"Rain and wind may change the oil's diffusion speed. … The problem we are concerned about is how to avoid the oil spreading to the high seas," the insider said.

Previous warnings unheeded

Another insider told People's Daily that the investigation has been handed over to State level. It is estimated that the preliminary result of the investigation will be released in two weeks, the paper said.

The total amount of crude oil that spilled into the sea remains unknown, but according to previous reports by China Central Television, the leakage is estimated to be 1,500 tons.

According to the local pollution-control and prevention laws, enacted on March 1, an accident that causes a spill of more than 1,000 tons of oil or direct economic losses of 200 million yuan ($29.5 million) is classified as a top-level pollution case and should be investigated by the State Council or transportation departments authorized by the State Council.

The risk of fire and explosion in the tank area of Xingang Harbor was warned of a year ago.

An evaluation report carried out by the Oil Projects Safety Evaluation Company in Beijing in April 2009, put the risk at a "serious" level.

The report said fire and explosions are easily triggered in the process of crude oil storage and transportation due to leakage.

China is the world's second-largest oil importer and the largest in Asia.

In 2009, China imported 204 million tons of oil, according to statistics from the General Administration of Customs, and 90 percent of the oil is imported via ships.

During the decade from 1998 to 2008, there were 733 cases of shipping pollution in China that seriously harmed the marine environment.

In 2008 alone, there were 109 cases of oil spills leading to a 354-ton leakage of oil.

Yang Ailun, head of Climate and Energy at Greenpeace China, told the Global Times that it is becom-ing more and more obvious that it is unsustainable to build our economic development on polluting fossil fuels.

Yang urged the government to reform the energy system by improving energy inefficiency and developing renewable energy.

Liu Linlin and agencies contributed to this story