Paraffin spilled on Vlieland
On the North Sea beach, paraffin was washed on the island of Vlieland.
Paraffin, which looks like candle wax, is often used to clean shipyards. A plane was searched for the perpetrator on Monday, but not found, said a spokesman for the Rijkswaterstaat.
Rijkswaterstaat starts cleaning the beach on Tuesday.