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:
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Sunshine all day tomorrow and warm week ahead
Lovely and warm with highs of 23 and 24 degrees. Hottest on Wednesday.
Searches are being carried out in Nunney in Somerset for 86-year-old Kenneth Scotcher.