Wyre Council said people should stay out of the sea at Cleveleys following an oil spill, while signs at Bispham also warn beach-goers against entering the water.
Oil and tar balls were seen in the tide and on the sand between Red Bank Road and Norbreck Castle in Bispham on Sunday, and have since been spotted as far north as Cleveleys, Fleetwood, Knott End, and the River Wyre, and as far south as North Pier.
As reported by The Gazette yesterday, samples of the thick gunk - which stinks of diesel-like fuel - has been collected by Coastguard officers and sent off for assessment by counter-pollution experts in Edinburgh.
This morning, Wyre Council said it was urging people to avoid contact with 'any visible oil or tar on the beach and in the water, to supervise children carefully, and keep your dog on a lead'.
It said the sea at Cleveleys has been closed to bathers as a precaution, and said the Fleetwood to Knott End ferry service is not running due to oil deposits on the ferry slip.
A spokesman for Blackpool Council said posters have been put up at Bispham warning of an 'abnormal situation', with people told not to bathe or paddle in the water there.
Signs have also been posted up at Wyre, including at Rossall, where there was no visible sign of any spill but a strong smell of fuel in the sand.
Last night, it was still busy with dog walkers unaware of the pollution incident.
A spokesman for the Maritime and Coastguard Agency said it had ‘been made aware of spots of what appears to be heavy oil and tar balls being washed up’, and said experts were working with a number of different departments.
“Samples of the oil are being sent for tests to see if the source can be identified,” he said.
“Braemar Response are on the scene and are working to remove pollutants from the beach.”