The source of a mystery substance being washed up on beaches along the Fylde coast remains unknown, officials said.
The chunks of bright orange fatty balls, which stink of fuel, have been found on the sand at St Annes, Cleveleys, Fleetwood, and Knott End in recent days.
There have been reports of it washing up at Norbreck and Starr Gate too, although Blackpool Council said it had 'no confirmed reports of any deposits on its beaches'.
READ MORE: Mystery substance 'likely' to be toxic palm oil - sparking warning to parents and dog walkers
Tests are being carried out to find out whether the substance is, as feared, toxic palm oil, which is harmless to humans but potentially deadly to dogs.
Pet owners have been told to keep their animals on a lead, while children should be supervised, Wyre Council said.
Beaches remain open, but people should 'avoid all contact with residue' on the sand and in the water 'due to potential health risks', it said in a statement.
Council rangers are patrolling Wyre beaches, while the beach patrol teams are surveying the coast in Blackpool.
It added: "Wyre Council, Blackpool Council, Fylde Council, and the Environment Agency are aware of a substance which has been washed up on the Lancashire and south Cumbria coast line.
"There are numerous suggestions as to the source of the material, however this has not yet been confirmed."
In March, Anglesey Council said palm oil that washed up near Trearddur Bay, on the north west tip of Wales, may have come from a ship that capsized 26 years ago, killing 10 crew members.
The Daily Post said recent storms are believed to have moved the wrecked Maltese vessel, Kimya, which sank 16 miles south west of Holyhead in 1991, and dislodged the oil.
And after oil was spotted near Trearddur Bay again last week, Lytham Coastguard station officer Paul Little said it is a 'possibility' that the same batch of oil has drifted up to the Fylde coast.
There are also local media reports of dogs eating suspected palm oil on the beach at Seascale in Cumbria, and chunks of bright yellow material washing ashore in Barrow, in recent days.