Surfers and swimmers have been warned to steer clear of some west Cornwall beaches after a mystery 'killer' substance was found.
A dog that ate the substance, described as white and glutinous and likely vegetable oil-based, died from its effects, while others have been made sick, warn vets.
According to the Falmouth Packet, a Penzance vet said a miniature schnauzer had died after eating the white object at Long Rock beach on Tuesday.
Cornwall council has now put up public health warning signs at beaches that read: "There is a pollution incident affecting the beaches and water in this area".
The substance is being analysed by the Maritime and Coastguard Agency (MCA) and has been described by health officials as worrying.
Dr Femi Oshin, from Devon, Cornwall and Somerset Public Health England (PHE), told the BBC and the Falmouth Packet: "We are advising people to avoid contact with the substance.
"At this stage we are not aware of any human health issues but if you do come into contact with the substance, please wash it off using normal soap or shower gel and water and wash your clothes.
The beaches affected include Praa Sands, Porthcurno and Penzance promenade, but there are warnings it could travel to other Cornish beaches over the next few days.
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