Toxic palm oil continues to wash up on beaches across the Fylde coast, more than a month after it was first spotted.
The appearance of the toxic substance, which can prove fatal to dogs, sparked health warnings, with people told to keep their pets on a lead and their children supervised.
Officials initially suspected the oil, described as 'fatty, oil, greasy with a rancid aroma and bright in colour', may have been dislodged from a shipwreck 16 miles south west of Holyhead during stormy weather.
But they are now considering whether it came a ship washing out its tank in the Atlantic ocean, one person involved in the clean-up operation said.
The oil is still washing up on an 'almost daily basis', a spokeswoman for Wyre Council added, with beach patrol staff working to clear it away.
The council again called on readers to report the oil by calling 01253 895116. They should say when and where it was seen, its estimated size and quantity, and the colour of the deposit.
"The beaches remain open, however we advise to keep children supervised and to avoid all contact with palm oil on the beach and in the water due to potential health risks," it said in its last update.
"The strong smell of the oil can attract dogs to sniff or eat it, however it is highly toxic to dogs so owners must keep dogs on a lead at all times when on the beach."
Palm oil first started washing up in Cleveleys, Fleetwood, and Knott End at the start of last month, sparking an alert by the Coastguard.
It was later spotted in Blackpool, where there were also local media reports of a similar substance washing ashore in Cumbria and Wales.
Tests were carried out to find out what exactly had been washing up, just months after oil and tar leaked from an off-shore storage tanker also had to be cleaned off the beaches.
Almost 20 tonnes of waste, including oil, sand and stone, was removed, with beaches ordered off limits, and the Fleetwood to Knott End ferry service suspended because the slipway was too treacherous.
The shellfish at Knott End Spit and Sea Centre South in Knott End was also closed.
Samples sent to a lab in Edinburgh later shared Eni UK's offshore storage installation, in Liverpool Bay, as the source of the spill.
The oil giant said between two and 20 tonnes of oil leaked there in early July, and said it informed authorities 'immediately'.
It was heavily involved in the clean up, and later made the subject of an investigation by the Department for Business, Energy and Industrial Strategy.
A specialist group was also set up to monitor any impact on marine or wildlife, though there were no reports of any.