The Suffolk County Department of Health Services has confirmed new cyanobacteria blooms, commonly known as blue-green algae, in Merritts Pond in Riverhead and Laurel Lake in Laurel.
The blooms were identified through analysis of surface water samples conducted by Stony Brook Southampton.
Health officials are urging residents to avoid contact with the affected waters and to keep children and pets away from the areas.
Although blue-green algae naturally occur in lakes and streams in small amounts, under certain conditions they can rapidly multiply into harmful blooms. The algae may appear as green, blue-green, yellow, brown or red discoloration, floating scum or water with a paint-like appearance.
Officials advise avoiding any water that looks discolored or scummy. Anyone who comes into contact with affected water should rinse off immediately with clean water. People experiencing nausea, vomiting, diarrhea, skin, eye or throat irritation, allergic reactions or breathing difficulties after exposure should seek medical attention.
Residents can view a statewide map of harmful algal blooms and find additional information through the Suffolk County Department of Health Services, the New York State Department of Health and the New York State Department of Environmental Conservation.