Residents and visitors have been warned to avoid mystery substances found on a number of Anglesey beaches.

Deposits of white and yellow fatty substances have been washed ashore on the North West coast of Anglesey in recent days.

Natural Resources Wales are currently testing the substances that have been found, however, they are believed to either be palm oil or vegetable oil, which are dangerous to dogs if ingested.

Staff from the County Council’s Maritime Section have been collecting the deposits, which vary in size.

The white substance has been found at a number of beaches, including Porth Nobla, Tyn Towyn, Cymyran, Aberffraw and Rhosneigr.

On Wednesday, November 8, a ball of yellow fatty substance was also found on Cemaes beach.

Anglesey’s Maritime Officer, Iwan Huws, has been leading the effort to clear the substance from Anglesey beaches.

“We’re received a large number of notifications from the public about these substances.” he said. 

“We’re grateful for the information provided and have been trying to collect them as quickly as possible. We have also been informed that a number of dogs have become ill after ingesting this substance.

“Our beaches remain open but it advised people to avoid contact with the greasy residue, supervise children carefully and keep dogs on a lead.”

The County Council’s Maritime Section is being supported by Natural Resources Wales which are carrying out tests to identify the substance.

Sian Williams, leading on the incident for Natural Resources Wales, said: “We have fantastic beaches in Wales so it’s important we look after them for people to enjoy.

“There are reports about a yellow substance being washed up on Cemaes beach on Anglesey. We are trying to establish what it is, but it could be something like vegetable or paraffin oil.

“We are working with Isle of Anglesey County Council to tackle this, as well as the white palm oil which has affected beaches in the area, and would advise people to listen to advice and keep their dogs on a lead.”

“Our local reserve manager in Newborough is also working to clear the white palm oil and put up warning signs around the beach at Llanddwyn.”