Mill Pond Tainted by Algae

A bloom of cyanobacteria, or blue-green algae, has been detected in Mill Pond in Water Mill. The toxic algae also persist in Lake Agawam in Southampton, Roth Pond in Stony Brook, and Lake Ronkonkoma. 

Sampling conducted by officials at the State University at Stony Brook confirmed the presence of cyanobacteria in Mill Pond, according to a statement issued Friday by the Suffolk County Department of Health Services. Officials have advised residents not to use, swim, or wade in the affected waters and to keep pets and children away from the area. 

Though blue-green algae are naturally present in lakes and streams in low numbers, they can become abundant, forming blooms in shades of green, blue green, yellow, brown, or red. They may produce floating scums on the surface of the water or may cause it to take on a paintlike appearance. 

Contact with waters that appear scummy or discolored should be avoided. If contact does occur, one should rinse with clean water immediately, and seek medical attention if nausea, vomiting or diarrhea, skin, eye, or throat irritation, or allergic reactions or breathing difficulties occur after contact. 

The Health Department’s office of ecology can be called at 631-852-5760 between 8:30 a.m. and 4:30 p.m., or emailed at, to report a suspected blue-green algae bloom at a body of water that contains a Suffolk County-permitted bathing beach. To report a suspected cyanobacteria bloom in a body of water that does not contain a permitted bathing beach, residents have been asked to contact the Division of Water at the State Department of Environmental Conservation at 518-402-8179 between 8 a.m. and 4 p.m. or via email at 

The D.E.C.’s notification page for harmful algal blooms, at features a comprehensive list of affected water bodies.