Suffolk County health officials have confirmed the presence of blue-green algae in Maratooka Pond in Mattituck and are warning residents to avoid contact with the affected water.
Sampling performed by SUNY Stony Brook found a cyanobacteria bloom in the pond and the health department is advising residents not to use, swim or wade in the water and to keep pets and children away from the area.
Contact with cyanobacteria can cause nausea, vomiting or diarrhea, skin, eye or throat irritation, allergic reactions or difficulty breathing.
Blue-green algae are naturally present in lakes and streams but pose a danger when they become abundant. Blooms may produce floating scum on the surface of the water.
A cyanobacteria bloom was also discovered at Georgica Pond in East Hampton.