The oil spill in China's largest offshore oilfield, in northern Bohai Bay, has still not been contained nearly two months after the problem emerged, authorities say.
The State Oceanic Administration said on Thursday that it had identified several oil sheens across a 4.6-square-kilometre area east of the Penglai 19-3 oilfield, off the coast of Shandong province. The facility is operated by US firm ConocoPhillips and the China National Offshore Oil Corporation (CNOOC).
The latest detection of leaking oil comes after ConocoPhillips China's president Georg Storaker said on July 6 that the main spill had been contained and the clean-up was nearly finished. The company said no oil slicks had been found on the coast after it was asked to halt production in the affected areas on July 13.
But the administration said the oilfield's platform C was leaking at 2.52 litres per day and that 20 to 70 oil sheens were emerging every minute. Oil slicks were also found near platform B. It said the production wells, recharge wells and water injection wells of both platforms were closed.
Lin Fangzhong, an official with the administration's North China Sea branch, was quoted by Xinhua as saying the density of oil pollutants per litre of sea water sampled in the area was as high as 118 micrograms, more than twice the acceptable limit of 50mcg.
According to the American Petroleum Institute, a spill of seven barrels (1,123 litres) of oil can be considered a serious incident. Greenpeace China said that while last year's BP spill in the Gulf of Mexico reached 5,000 barrels a day, the effects of just 2.52 litres of oil leaking continuously from the Penglai oilfield could be underestimated because the Bohai Bay environment was different and the incident was ongoing.
The administration has ordered ConocoPhillips to clean up the areas and hold a thorough investigation by August 31 to avoid any further leaks.
The company said: 'Any oil that is seeping near platform B is in very small amounts, and is contained and cleaned up quickly. At platform C, occasional sheens are generated as we continue our sub-sea clean-up efforts of the oil-based drilling fluids from the sea floor. These sheens are also being contained with absorbent booms and cleaned up quickly before they leave the field.'
However, environmentalists were sceptical the clean-up would meet the August 31 deadline.
They said the detection of new oil sheens, and the northward spread of the spill to the coasts of Hebei and Liaoning provinces, showed the problem was more serious than previously thought. 'It shows that the action taken by the company is not effective enough,' said Ma Jun, an expert in water pollution. 'We are seeing more spills every day.'
Professor Wang Yamin, from the Marine College at Shandong University in Weihai, said the clean-up would take a 'very long time'.
'The creatures deep under the sea are very sensitive to acid, and it involves a great deal of resources to check the damage to the ecosystem at that depth,' he said.