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Suffolk County health officials are warning residents to stay out of Forge Pond and Peconic Lake in Calverton after Stony Brook University researchers confirmed new cyanobacteria blooms, more commonly known as blue-green algae, in those water bodies.

Blooms have also returned to Old Town Pond in Southampton, the health department said.

The new findings bring to nine the number of water bodies in Suffolk affected by the
blooms of cyanobacteria, which can cause gastrointestinal illness and irritation of the eyes and upper respiratory tract.

Health officials ask residents not to use or swim or wade in these waters and to keep their pets and children away from the area.

The affected bodies of water are:

Forge Pond/Peconic Lake – Calverton
Maratooka Pond, Mattituck
Old Town Pond – Southampton
Agawam Lake, Southampton
Wainscott Pond- Wainscott
Georgica Pond- East Hampton
Mill Pond – Watermill
Spring Lake, Middle Island
Setauket Mill Pond- Setauket

Though blue-green algae are naturally present in lakes and streams in low numbers, the health department said, they can become abundant, forming blooms mostly typically in shades of green but also in shades of blue-green, yellow, brown or red. They may produce floating scums on the surface of the water or may cause the water to take on paint-like appearance.

Contact with waters that appear scummy or discolored should be avoided, officials warn.

The health department issued the following recommendation if contact does occur: rinse off with clean water immediately. Seek medical attention if any of the following symptoms occur after contact: nausea, vomiting or diarrhea; skin, eye or throat irritation; or allergic reactions or breathing difficulties.

To report a suspected blue-green algae bloom that is in a body of water that does not contain a Suffolk County permitted bathing beach, contact the Division of Water at New York State DEC: 518-402-8179 between 8:00 a.m. – 4:00 p.m. or anytime via email at

To report a suspected blue-green algae bloom at a body of water that does contain a Suffolk County-permitted bathing beach, contact the Suffolk County Department of Health Services’ Office of Ecology at 631-852-5760 between 8:30 a.m. – 4:30 p.m. or by email at any time at

For a comprehensive list of affected waterbodies in New York State, visit the DEC’s Harmful Algal Bloom Notification Page at
For more information about blue-green algae, visit the Suffolk County website:

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Denise is a veteran local reporter, editor and attorney. Her work has been recognized with numerous journalism awards, including investigative reporting and writer of the year awards from the N.Y. Press Association. She was also honored in 2020 with a NY State Senate Woman of Distinction Award for her trailblazing work in local online news. She is a founder, owner and co-publisher of this website.Email Denise.