People are being advised not to swim or paddle in the sea at Blackpool north, central, and south, Fleetwood, Cleveleys, and Bispham.
It comes after oil thought to have come from a ship 18 miles off the coast last week washed ashore, leaving experts scrambling to clear up the spill.
Signs have been put up along the coastline as far north as Knott End, where the ferry service has been suspended because of the treacherous slipway, warning people of an 'abnormal incident'.
Some 72 25kg bags of globules and chunks of tar-like black substance, as well as sand and stone - weighing around two tonnes - have been removed from Bispham and Blackpool beaches by specialists so far.
And 165 bags have been removed from beaches in Wyre - around four tonnes - though more work still needs to be done there.
A spokesman for Blackpool Council said: "The focus is now on removal of any oil smears on the sand and seawall, as well as regular monitoring for any further deposits coming in on the tide."
Samples of the oil were taken on Sunday and sent for testing at a lab in Edinburgh. The Maritime and Coastguard Agency said results were expected back within 72 hours, which means answers about where specifically it came from could be available today.
"Removal of this pollution is being undertaken with specialist contractors and as such, members of the public should not attempt to remove the pollution by themselves," the council added.
"The cleaning team should not be hampered in their removal of the pollution.
"As part of the removal, the cleaning teams will be wearing specialist equipment to remove the pollution.
"This is purely a precaution and people should not be alarmed when they see the cleaning teams.
"This cleaning could take several days to complete.
"As a precaution, bathing is not advised at Fleetwood, Cleveleys, Bispham, Blackpool North, Blackpool Central and Blackpool South bathing waters. Members of the public can still go on the beach but should keep clear of the pollutants.
"Members of the public are being advised not to touch, or pick up the pollutants."
A Coastguard spokeswoman had previously urged people to 'stay safe by staying away from the area until the clean-up operation is complete'.
She added: "There was an incident that resulted in the release of crude oil from a ship, more than 30 kilometres from the coast of north west England on Monday, July 10.
"We believe that the oil is from that incident, but until we have confirmation from the test results we cannot say for certain.
"The incident is relatively contained and Braemar are on scene leading with the clean-up operation."
It is not yet known whether the release was accidental or deliberate, but as decontamination units and beach workers fight to clear miles of coastline of the spill, fears have been voiced for the Irish Sea’s thriving marine life.
A number of dead birds were spotted among washed-up seaweeds by one dog walker, said to be cormorants by another man, while a dead porpoise was also investigated by the Coastguard.
That was found to be badly decomposed and not a victim of the spill, while no wildlife has been reported washed up, the Coastguard service said, but former animal lecturer at Myerscough College John Vale said: “It could affect the whole ecosystem. Any spill is too big.”
Mr Vale, who lives in Blackpool, said the oil could kill off basic microscopic life, which in turn could impact on larger marine animals.
But he warned wintering birds in the Wyre estuary could also be affected, and said: “Fortunately we have beaches you can get vehicles on and get rid of the oil.
“If it’s not, and it’s already flowing into the estuary, it could severely affect the winter population of birds.”
Clumps of black substance, which has left the sand reeking of fuel, began to wash up at Bispham at the weekend.
As it was spotted elsewhere, the sea was ordered off limits at both Cleveleys and Bispham yesterday.
Fleetwood to Knott End ferry skipper Tony Cowell said it was the first time he had ever experienced such a situation, and that he expects disruption today too.
“We just couldn’t operate the ferry for health and safety reasons," he said. “There were globules of this oil type substance all over the slipway at both Fleetwood and Knott End and it was incredibly slippy and dangerous.
“There is no way we would put passengers at risk and we were advised by the Coastguard Agency to stop operating until further notice.
“We were also worried about getting this stuff on passengers;’ clothes, it’s horrible stuff. They’d never get it out.
“We’ve been given a high pressure spray to use on everything on Wednesday and were told not to think of operating until we’ve got the all clear.”
He said people in protective suits had been on Fleetwood beach and samples of the substance had been taken away.
He also said people had been on the beach early on yesterday attempting a clean-up.
Those who may have already come into contact with the oil and tar-like spots have been urged to seek immediate medical advice should they start to feel unwell.
Posters were put up at Bispham warning of an ‘abnormal situation’, with people told not to bathe or paddle in the water there.
And A4-sized notices were also posted up at Wyre, including at Rossall beach, where there was no visible sign of a spill but a strong smell of fuel in the sand.
On Monday evening, it was still busy with dog walkers unaware of the pollution incident, while children were still playing on the beach at Cleveleys yesterday morning, despite chunks of oil lying in the sand nearby.
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’.
“The advice from Public Health England is that it is very unlikely that anyone exposed to crude oil for a short period of time will have any long term health effects,” it said in a statement.
“Short term exposure to skin may result in irritation so as a precaution members of the public are advised to avoid contact with the material.
“If you touch the tar balls and get oil on the skin, remove affected clothing and wash with soap and water for 10 minutes.
“If you feel unwell seek medical attention.”
Allan Wilkinson, 68, watched on as a decontamination unit arrived to clean up the beach and slipway at Knott End.
He said a horde of people in fluroescent jackets were clearing solidified oil from the beach in clear bags, and said: “There’s notices up right along the front warning people about taking their dogs on the beach and taking their kids on; basically they are warning people to keep off. “It’s worrying but it’s more annoying that we can’t go on the beach while it’s being cleaned up.”
If more oil is spotted, it can be reported by calling the council on 01253477477.
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