Chemists at Plymouth University have identified the sticky substance that has killed hundreds of sea birds off the Devon and Dorset coast.
Their findings suggest it's a form of Poly Isol Butene, or PIB, used as a lubricating additive in oils to improve performance.
Tamsin Eames reports:
More top news
Clear skies so frost overnight, leading to a very wet Sunday.
A dry evening, but Sunday is looking very wet!
Sunny spells continue this afternoon. Clear skies tonight could see a frost in the morning.