Falkirk Council are telling local people and pets to stay away from Millhall Pond near Polmont.
It's after increased concentrations of Cyanobacteria were found within the water there. The blue-green algae produces toxins which can cause nausea, fever, skin irritation, gastrointestinal issues or hay fever-like symptoms.
Anyone experiencing these symptoms after contact with affected water is urged to contact their doctor immediately.
Members of the public and pets are advised to avoid contact with the water, as well as any scums or mats on the shore. The local council also recommends any fish caught in Millhall Pond should not be eaten.
The nearby Millhall Reservoir/Fishery is not affected, and there's no adverse impact on any public water supplies. The local authority is putting up precautionary signs in the immediate area around the pond.
Councillor Paul Garner, Depute Leader of Falkirk Council said: "Visitors should avoid the Millhall Pond area for the meantime due to the risk posed by naturally occurring Cyanobacteria (blue-green algae).
"As a precaution we are installing signs in the immediate vicinity warning people and pets to stay away from the water."
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