A large slick of waste oil was spotted floating near a local ferry dock on the Huangpu River yesterday, according to Tuesday's Shanghai Daily.

While authorities cleaned up all of the waste by yesterday afternoon, they still don't know which ship illegally poured the oil into the river.

Work to clean up the slick began around 1:30 pm yesterday and finished about three hours later, officials said.

The incident didn't influence normal operations at the Ningguo Road Ferry Dock along the Huangpu River in Yangpu District.

About 30 workers from a professional oil cleaning service company were sent to clear the    water and polluted banks with special oil-absorbing paper.

Officials from the local maritime safety administration said it's very probable the oil leaked from a ship by accident.

"The waste oil will not cause considerable pollution to nearby waters," said Tang Yuecai, director of the Lanzhou Road Division of the administration, which looked after the incident.

Scattered oil stains floated within a 200-meter-long strip alongside the ferry bank yesterday afternoon and were contained by a floating bridge

Officials said the leak was too small to be harmful, as it didn't form any thick or large stains and was not detected anywhere else on nearby waters.

"It's lucky that the oil was brought down to gather near the riverbank by ebbing tides at noon. This gave us enough time to clear it off before it could spread out with rising tides late in the afternoon."

"But the floating bridge also blocked out our ships. The workers had to climb down the bank to approach the polluted areas."

Ferry workers discovered the floating oils around 8am and alerted authorities.

Maritime agents soon cruised the river and investigated a nearby port that stores oil.

No leaks were detected from the oil port, though. Officials said the waste diesel oil might have been mistakenly let out from a small cargo ship, judging from the situation.

The ship owner could sell the waste oil to an oil recycling station.

As pouring it into the river could lead to tough fines, few ship operators in the city are willing to run the risk of violating the rules.

The ship might have poured the wastes during the previous evening, officials said.

(Shanghai Daily June 1, 2004)