Maersk says checking North Sea oil slick sightings

COPENHAGEN (Reuters) - Danish shipping and oil group A.P. Moller-Maersk said on Thursday it was investigating sightings of an oil slick near three of its North Sea fields but that it could not identify any spill.

Oil on the surface of the sea was observed by Danish and German reconnaissance aircraft on Tuesday and Wednesday near the Dan, Halfdan and Kraka fields in the North Sea, Maersk Oil said in a statement on Wednesday.

An official at the Danish Environmental Protection Agency (EPA) said the slick was estimated to measure 300 square kilometers, but the EPA did not consider it to be a serious spill and the oil would not reach the shore.

"The oil has been observed, and right now we are investigating," Maersk Oil spokesman Thomas Grondorf said on Thursday.

The company said it was working closely with the relevant authorities, but that it had not been able to identify anything unusual in its discharges.

"Our data does not indicate an oil spill, but we would rather activate our environmental protection measures one time too many," said Franz Willum Sorensen, head of Maersk Oil's Danish activities, in the statement.

Anna-Cecilie Skovgaard, a technician at the Danish EPA, said an estimated 73 cubic meters of oil had been spilled, according to a German reconnaissance flight with radar on board and visual observation.

"We do not judge it as serious," Skovgaard said. "That is based on our judgment of what we see as a probable environmental impact of this spill."

"It will not reach the shore," she said. "The calculations of the drift show that it is very steady -- there is no current in the area."

She said an oil sample from the slick would be analyzed to trace the source. "We have indications from drift calculations that it comes from the Dan installation," she said.

But she said the authorities were still awaiting the results of the analysis of the oil sample, and it was not ruled out that the spill could be from a vessel.

The Dan installation produced 54,300 barrels per day in April.

News of the oil slick came as BP continued its efforts to contain a major oil spill in the Gulf of Mexico, which began last month.

(Reporting by John Acher, Editing by Jane Baird)