China has closed the Dalian Xingang oil port in its northeast, home to the country's largest oil reserve bases, after crude pipeline explosions spilt oil into the sea.
State oil major PetroChina, which operates two major refineries in Dalian, has set up a contingency plan to cope with one week's closure of the main oil port that receives foreign crude vessels regularly and also a main export point for gasoline and diesel.
PetroChina has started trimming refinery operations at one of the plants, the 200,000 barrel-per-day (bpd) West Pacific PetroChemical Corp (WEPEC), by about "several thousand tonnes" per day.
"The port was sealed right after the explosion. We have a one-week contingency plan, but are hoping that the oil spill can be cleaned up as soon as possibly," the oil executive told Reuters on Monday.
Dalian Port said in a statement to the Hong Kong stock exchange that the incident had not caused any direct damage to the oil terminal's main facilities, the impact being limited to ancillary facilities such as control systems.
"The magnitude of the damages and losses caused by the accident and its impact on the operations of the Group and Dalian Petro China Warehousing remain to be further assessed," it said.
Maritime safety authorities are also battling to contain a 50 sq km (19 sq mile) oil slick after two crude oil pipelines exploded in the northeastern port of Dalian, state media added.
The oil executive said contamination on about 10 sq km of sea area was "quite serious."
Hundreds of firefighters battled for more than 15 hours to extinguish the blaze that started late on Friday when a pipe transporting crude oil from a ship to a storage tank blew up, causing a second pipeline nearby to explode.
The incident drew the attention of top Chinese officials, including president Hu Jintao, premier Wen Jiabao and security chief Zhou Yongkang, who all issued statements and instructions during the blaze.
There were no casualties, but state television said oil had contaminated the ocean off the port city in Liaoning Province.
Workers are using skimmers and dispersants to break up the oil slick and stop it spreading, the official China Daily said. The pollution is concentrated about 100 km (62 miles) offshore.
"By Sunday evening, about 7,000 metres of floating booms had been set up and at least 20 oil skimmers were working to clean the spill," the newspaper quoted local officials as saying.
There are no residents within 3 km (1.8 miles) of the affected site, and little "marine farming," the report added.
The blast happened when a Liberian-flagged tanker was off-loading oil, the China Daily said.
The cause of the blast is under investigation, and CNPC, the parent of PetroChina, said monitoring of the air and sea environment had been stepped up in the affected areas.
Reuters