The thick oil was out in the water, but some also drifted onto the beaches in Hittarp, Domsten, Viken, Lerberget and Höganäs.
The affected municipalities, Helsingborg and Höganäs, were forced to block off and clean up the bathing areas.
In addition, the marine nature reserve Grollegrund, which has a rocky beach that is more difficult to clean from the oil, was affected.
Still unclear from where
But where the oil comes from is still an unsolved mystery.
According to the county administrative board, it is not usual for ships to clean their tanks in the Sound.
However, it may have been carried to the coast by currents.
But where the oil comes from is still an unsolved mystery.
Photo: Johnny Johansson
The Coast Guard opened a criminal investigation, but it is now closed.
- We have no suspect.
There are so many ships passing through Öresund, says Karin Cars, communicator at the Coast Guard.
Can be picked up again
She also says that no new oil has been sifted.
- But if new information comes to light about where the oil comes from, we can take up the criminal investigation again, says Karin Cars.
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Between Saturday evening and Sunday morning, the rescue service urged everyone to avoid contact with water, after oil spills were found on beaches.
Photo: Johnny Johansson