Members of the public are being advised to steer clear of the sea at Heysham following a suspected diesel spill.
Lancaster City Council are working with HM Coastguard to assess the situation following reports of pollution washing up at Half Moon Bay.
It is understood the diesel has leaked from a vessel out in Morecambe Bay.
A spokesman for Lancaster City Council said: “We’d advise people to stay off the stretch of coast between Heysham Village and Half Moon Bay.
“We are working with the coastguard to assess the situation, and have called in a contractor to clean it up.”